Boundary spanners and the external market reach of clusters: the case of the Jingdezhen ceramics cluster in China

ABSTRACT Extra-local linkages are increasingly understood as key drivers of cluster development. The literature, however, tends to be overwhelmingly concerned with global production and knowledge linkages, paying insufficient attention to extra-local market linkages. To address this research lacuna, through a case study of the Jingdezhen ceramics cluster in China, the paper investigates the ‘market reach’ process to unpack how diverse individual actors, conceptualized as ‘boundary spanners’, have enabled this cluster to forge extra-local market linkages. More specifically, it identifies three market reach mechanisms, namely: convening quasi-permanent clusters locally, facilitating participation in external temporary clusters and establishing one-to-one market relationships.


INTRODUCTION
Since the early 2000s, exogenous forces have increasingly been considered as key drivers of cluster development. Economic geographers and cognate researchers have long since recognized that links to global knowledge sources and production networks are fundamental for clusters to avoid lock-in, foster innovation and capture developmental opportunities (e.g., Coe et al., 2004Coe et al., , 2008De Marchi et al., 2018;Humphrey & Schimitz, 2002). A subset of this research has highlighted the micro-level processes of cluster externalization and globalization, showing how the agency of diverse actorsincluding firms, public research institutes, government agencies and mobile individualsallows clusters to establish extra-local and global linkages (e.g., Dawley et al., 2019;Giuliani, 2011;Graf, 2010;Henn, 2012;Hervas-Oliver & Albors-Garrigos, 2014;Horner, 2017;Saxenian, 2002).
Such literature, however, tends to be overwhelmingly concerned with production and knowledge linkages, paying insufficient attention to extra-local, and oftentimes global, market linkages. Relatively little research has unpacked the obstacles that producers within a cluster may encounter in reaching external markets, and the processes through which clusters may become connected with external markets and buyers more effectively. This is an important lacuna, as it is only through the realization of value via market transactions that the development path of a cluster can be sustained, especially given the limited local market in most contexts. Market construction is thus a key but under-appreciated aspect of cluster development. As such, it is necessary to explore how specific actors actively help clusters establish and coordinate external market linkages through their interventions and agency.
To address this issue, this article mobilizes and develops the 'boundary spanner' concept from the management and organizational studies literature. First introduced by Aldrich and Herker (1977) in the late 1970s to illustrate the boundary roles of individuals in facilitating organizational innovation, this concept has subsequently gained prominence in research on organizational strategies and marketing (Haas, 2015). Applying this concept to cluster studies, Wu (2022) has proposed a theoretical framework illustrating how boundary spanners serve to 'globalize' clusters and thereby shape cluster development through four boundary-spanning functions: discursive construction, innovation promotion, production coordination and market reach. This present study further unpacks the market reach boundary-spanning function in particular by conceptualizing three specific market reach mechanisms, namely convening quasi-permanent clusters locally, facilitating participation in external temporary clusters and establishing one-to-one market linkages. Importantly, the literature on temporary clusters has paid considerable attention to the market/marketing dimension (Rosson & Seringhaus, 1995), thereby helping to resolve the lack of consideration of market linkages in cluster research more generally.
This paper contributes to cluster debates in two interrelated ways. First, it scrutinizes how the extra-local market linkages of clusters get constructed and coordinated through actor agency. Second, in bridging the literatures on temporary clusters and permanent clusters, it examines how temporary clusters, while being short-lived events, enable clusters to forge extra-local market linkages and in turn have lasting impacts on cluster development. In so doing, this paper also fills a research lacuna in the temporary cluster literature wherein insufficient research has investigated how temporary clusters contribute to local and regional economic development more broadly (Li, 2014).
These arguments are mobilized through a case study of the Jingdezhen (JDZ) ceramics cluster in China. The JDZ cluster, which was a declining and peripheral 'old' industrial district during the 1990s, has globalized and been rejuvenated into a dynamic creative hub since the mid-2000s. The analysis investigates how diverse resourceful individuals, including artists, designers and traders, have functioned as boundary spanners to assist JDZ's producers both producers of final products and subcontractorsin accessing and conducting business with external customers.
The paper is structured as follows. The next section reviews what we term the 'globally oriented' cluster literature, with a specific focus on the role of agency in cluster externalization and globalization. Thereafter, the conceptual framework is introduced by developing the boundary spanner concept in the context of forging extra-local market connections, paying particular attention to temporary clusters as a key instrument. The penultimate section illustrates three 'market reach' mechanisms, before the concluding section outlines a future research agenda in this area.

THE EXTRA-LOCAL CONNECTIONS OF CLUSTERS: THE MISSING MARKET DIMENSION
The cluster literature increasingly pays attention to the nature of extra-local connections and their impacts on cluster development. This work tends to be driven, however, by a 'productionist' logic (Coe & Yeung, 2015), overwhelmingly focusing on clusters' external knowledge and production linkages, while overlooking other types of connections, particularly in the market realm. This section examines the globally oriented literature focusing on knowledge and production networks, and the role of actor agency in allowing clusters to establish and coordinate such extra-local, and sometimes global, linkages.

The global knowledge and production linkages of clusters
Between the 1980s and the 2000s, heavily influenced by the new regionalism literature, cluster research was primarily endogenous in nature, emphasizing place-specific factors that provided a supportive local milieu for cluster growth (e.g., Maskell & Malmberg, 1999;Scott, 1988;Storper, 1995). However, over the subsequent two decades, the cluster literature has paid increasing attention to the importance of exogenous forces, that is, extralocal and global networks and resources, in shaping cluster development. First, it is increasingly recognized that knowledge is produced and circulated on a global scale, through both formal inter-or intra-firm connections, and informal, interpersonal networks (Coe & Bunnell, 2003). Specifically, Bathelt et al. (2004) developed the idea of 'global pipelines' to highlight the significance of communication and interaction channels between cluster actors and selected global partners for accessing external knowledge assets. Many studies have since demonstrated that establishing global knowledge pipelines facilitates the innovation performance of clusters, particularly with respect to radical, disruptive innovations (Albors-Garrigos & Hervas-Oliver, 2019). Furthermore, these global knowledge linkages have been shown to be especially crucial in underpinning the new path development of clusters with limited endogenous capabilities and resources, such as organizationally thin and peripheral clusters (Trippl et al., 2018).
Concurrently, the dialogue between the cluster literature and the burgeoning work on global value chains (GVCs) and global production networks (GPNs) has shed light on unpacking clusters' extra-local production networks. Such approaches conceptualize cluster developmentoften framed more broadly in terms of 'regional development'as a multi-scalar, relational process inevitably intertwined with developmental dynamics in other places enrolled into the networks (Coe et al., 2004(Coe et al., , 2008De Marchi et al., 2018;Humphrey & Schimitz, 2002). According to this literature, forces inherent to GVCs and GPNs, and especially the operating strategies of global lead firms, are a key determinant of the development paths of clusters. From this perspective, how a cluster 'plugs in' to GVCs/GPNsoften understood in terms of value chain governance and modes and types of strategic couplingshapes the power relations between clusters and global lead firms, the value captured within clusters, and their upgrading and developmental trajectories.
2.2. Forging extra-local connections: the role of actor agency A subset of this globally oriented literature has examined the processes through which global connections are established and coordinated through the actions and agency of specific actors. One well-established body of work concerns the role of technology or knowledge gatekeepers in transferring extra-local knowledge into clusters. Gatekeepers first identify, interpret and absorb extra-local Boundary spanners and the external market reach of clusters: the case of the Jingdezhen ceramics cluster in China 881 knowledge through their global exchange processes, and then diffuse and translate such knowledge to local cluster actors (Breschi & Lenzi, 2015;Maskell & Malmberg, 2007). Gatekeepers are also referred to as knowledge integrators (Buciuni & Pisano, 2018) or knowledge facilitators (Bathelt & Li, 2020). Three types of actors tend to fulfil these roles: firms, public institutions and knowledgeable individuals. First, global lead firms and dynamic local firms, both of which are highly externally oriented and technologically advanced, are found to function as gatekeepers. They tend to participate in GVCs/GPNs and orchestrate a cluster's local production networks simultaneously, so that they both have access to external knowledge and possess channels of local knowledge diffusion (De Marchi et al., 2018;Giuliani, 2011;Graf, 2010;Hervas-Oliver & Boix-Domenech, 2013). Specifically, local knowledge dissemination can be achieved through informal interactions, formal modes of cooperation, labour mobility, and the creation of spin-offs by and from these lead firms (Cantner et al., 2010).
However, there are also limitations associated with private firms functioning as technology/knowledge gatekeepers. First, lead firms with strong knowledge bases and tight external connections tend to have little incentive to interact with less knowledge-endowed local firms (Giuliani & Bell, 2005). In such circumstances, knowledgeable firms tend to disseminate their knowledge as a 'club good' only to a small number of selective local actors, particularly those who are similarly technologically advanced (Giuliani, 2011;Morrison, 2008). Second, firm gatekeepers tend to be reluctant to destabilize the status quo and their network centrality, and are thus more likely to introduce only incremental innovations rather than radical technological changes (Hervas-Oliver & Albors-Garrigos, 2014).
Several studies have found that, instead of private firms, public institutions (e.g., research institutes and universities) are better positioned to act as technology/knowledge gatekeepers (Bathelt & Li, 2020;Belso-Martinez et al., 2018;Kauffeld-Monz & Fritsch, 2013). In a similar way to private firms, they are exposed to cutting-edge knowledge, and possess a high capacity to absorb such knowledge (Cohen & Levinthal, 1990). Most importantly, compared with private firms, public institutions are more likely to function as gatekeepers since they often have incentives to disseminate their knowledge pervasively as part of their public mission.
In addition to lead firms and public institutions, knowledgeable individuals such as transnational entrepreneurs can also help clusters establish global knowledge pipelines. These individuals, as carriers of embodied knowledge, can transfer expertise and know-how between places via their own mobility (Coe & Bunnell, 2003). They are effective in transferring knowledge by making use of their interpersonal and social networks, often through close-knit epistemic communities, characterized in the literature as communities of practice (Amin & Cohendet, 2004;Faulconbridge, 2010) and transnational technical communities (Saxenian, 2002;Saxenian & Hsu, 2001).
While the above literature demonstrates how the global knowledge pipelines of clusters are established, other work examines how their global production linkages are constructed and coordinated. A few GPN-inspired studies have examined how government actors at various levels facilitate the 'plugging in' of clusters to GPNs through their interventions, which are referred to as 'extra-firm bargaining' (Coe & Yeung, 2015). On the one hand, they can play a 'facilitator' role (Horner, 2017), shaping the assets of clusters so that they better match the needs of global lead firms, through a combination of economywide 'horizontal' policies and industry-specific 'vertical' policies (Dawley et al., 2019;Lee et al., 2014). On the other hand, in coalition with other actors, they may bargain with lead firms to encourage higher value capture for their clusters and to attain more balanced coupling relations (Coe & Hess, 2011). In addition to government agencies, transnational entrepreneurs (Yeung, 2009) and investment promotion agencies (Phelps & Wood, 2018) are also found to fulfil the role of constructing strategic couplings between clusters and GPNs.
In sum, the extant globally oriented literature has primarily focused on extra-local knowledge and production linkages at the expense of other types of connections, particularly market connections. Relatively little research has unpacked how producers sell final products to external markets, and how local subcontractors become connected to external customers, through actor agency. The transnationalism literature has examined how transnational entrepreneurs, using ethnic and family networks, conduct business activities between their host countries and places of origin (Drori et al., 2009). However, with a few exceptions (Henn, 2012;Saxenian, 2002;Saxenian & Hsu, 2001), this work tends to focus more on how ethnic and kinship networks enable transnational entrepreneurs themselves to do business across different countries. By contrast, this present paper shows how individual boundary spanners connect other actors (i.e., producers and buyers) and mediate their relationships.

BOUNDARY SPANNERS: BROKERING STRUCTURAL HOLES AND INCREASING PROXIMITY
This study advances the 'boundary spanner' concept, originating from management and organizational studies, to unpack how resourceful actors, acting as boundary spanners, can help clusters establish extra-local market linkages and in turn shape cluster development. In an important early contribution, Leifer and Delbecq (1978, p. 41) defined boundary spanners as 'persons who operate at the periphery or boundary of an organization, performing organizational relevant tasks, relating the organization with elements outside it'. Specifically, boundary spanners facilitate transactions and information flows between separated actors who either lack physical/cognitive access to one another or a basis for mutual trust (Long et al., 2013). Such functions can be undertaken by multiple actors from an organization regardless of their formal positions (Williams, 2012). As such, boundary spanners are often conceptualized as occupying a functional role: all the actors performing boundary-spanning activities (to be discussed below) are considered boundary spanners. Wu (2022) has applied this concept to cluster studies, proposing a theoretical framework to illustrate how boundary spanners serve to 'globalize' clusters and shape their development trajectories. While the concept originally refers to actors managing organizational boundaries in management and organizational studies, in Wu's framework, boundary spanner refers to actors spanning cluster boundaries to help a cluster create and coordinate extralocal, and potentially global, networks. They do this by constructing and influencing relationships between actors within and outside the cluster, who are otherwise unconnected or lack shared understanding. The present study develops further the market reach boundary-spanning function identified by Wu (2022).
According to Wu (2022), there are two major obstacles that local actors in a cluster often face when accessing global markets. First, identifying where the market is and who the potential customers are tends to be a difficult task. Such processes can be hampered by limited, imperfect knowledge regarding potential market destinations and customers (Kapur & McHale, 2005). Second, when accessing external markets, cluster firms may suffer from variants of the so-called 'liability of foreignness', that is, the 'costs of doing business abroad that result in a competitive disadvantage' (Zaheer, 1995, p. 342), leading to considerable institutional, cultural and relational disconnects with distant buyers. The interventions of third-party boundary spanners are thus required to address these two problems and enable clusters to establish extra-local market connections.
In the management and organizational studies literature, a key role of boundary spanners is networking, which involves constructing and coordinating networks between members of an organization and external actors. First, according to these studies, boundary spanners with abundant connections to actors both within and outside an organization, construct connections to bridge across 'structural holes' (Burt, 1992) between parties that are otherwise disconnected (Cross & Parker, 2004). In this regard, boundary spanners behave as 'brokers' or 'connectors' of relationships. Brokering is important for a cluster to tackle the first aforementioned obstacle in accessing global markets, by helping identify and connect to appropriate external customers in the first place in order to forge market linkages.
Second, according to the management and organizational studies literature, boundary spanners are also 'interpreters and communicators' (Williams, 2012), who liaise, gatekeep and collaborate with actors within and outside an organization in order to coordinate and influence their interconnections. This helps smooth out social, cultural and institutional differences between the two parties and ensure that shared meanings and understanding can be created. Such a role is crucial in addressing the 'liability of foreignness' that cluster firms may face when accessing global markets, by reducing frictions resulting from cultural differences between local firms and distant customers embedded in different institutional contexts. In other words, this role requires boundary spanners to help generate various forms of proximity (cognitive, organizational, social and institutional) (Boschma, 2005) between the two parties.
In this context, how do boundary spanners broker structural holes and increase proximity between cluster firms and external buyers? First, temporary clusters, such as trade fairs, provide a potential mechanism. Since the mid-2000s, a large literature on temporary clusters has emerged, predominantly emphasizing the knowledgeoriented functions of temporary clusters by unpacking the 'global buzz' offered by these events (e.g., Bathelt & Li, 2020;Bathelt & Schuldt, 2010;Li, 2014). However, rich communication and knowledge ecologies are largely a by-product of temporary clusters, and the market-/transaction-oriented functions of temporary clusters should not be overlooked. Indeed, it is well recognized in the economic geography and business literatures that such events serve as crucial marketplaces wherein firms access typical attendees (i.e., prospective external buyers) (Borghini et al., 2006) and thereby establish and maintain global market linkages (Rosson & Seringhaus, 1995). For instance, Bathelt et al. (2017) found that trade fairs enable four types of transaction modes between exhibitors and visitors: classic deal-making; long-term stable customer relations; immediate synchronized customization; and follow-up negotiations. As such, temporary clusters are a fundamental marketing instrument that can be used by boundary spanners in facilitating 'market reach'. Boundary spanners can either convene temporary clusters locally (when these events take place regularly and consistently, they become quasi-permanent clusters), or help local producers to attend external temporary clusters. Second, interpersonal networks and social ties can be critical in forging extra-local market linkages (Henn, 2012). As such, in market reach, boundary spanners also construct and coordinate one-to-one market linkages between individual cluster firms and external buyers through such networks.

RESEARCH CONTEXT AND METHOD
We now move on to provide important background context on the JDZ cluster and its recent revival before considering the methodology that was deployed in the study.
4.1. JDZ: from a declining and peripheral old industrial district to a dynamic and international creative hub The JDZ ceramics cluster is located in Jiangxi province in south-east China. It is the so-called 'Porcelain Capital of the World', with a history of producing ceramics going back over a millennium (Gillette, 2016). Historically, JDZ used to dominate China's ceramic exports: between the 16th and the early 18th centuries, Europeans succumbed to the so-called 'porcelain disease' by purchasing massive amounts of JDZ ceramics.
Between 2002 and 2019, the overall output of the ceramics industry in JDZ rose significantly from 1.68 billion RMB (US$0.2 billion) to 42.3 billion RMB (US$6.13 billion) (Jingdezhen Statistics Bureau, 2020). Specializing in artistic/ornamental ceramics and aesthetic daily-use ceramics, JDZ is similar to a 'Third Italy' industrial district for two reasons. First, in contrast to other major ceramics clusters in China such as Zibo and Foshan, JDZ is dominated by small-and medium-sized enterprises (SMEs). JDZ's SMEs produce (semi-)handmade, small-batch, individualized products with high levels of design input, and each enterprise tends to specialize in specific market niches. Second, firms in JDZ have low degrees of vertical integration, and production is mainly carried out through collaboration among a large number of small firms/workshops (Fang, 2000).
JDZ experienced severe industrial decline and became highly peripheral during the 1990s (Gillette, 2016). Between the 1950s and the early 1990s, the cluster was dominated by state-owned enterprises (SOEs), which advanced the techniques in ceramics production significantly. Nonetheless, these SOEs became increasingly redundant and unable to compete in the market economy of the early 1990s, and all went bankrupt. In response, most of the laid-off workers subsequently set up private small-scale workshops to produce cheap, low-quality products with little innovation and design input. Meanwhile, JDZ had also become highly inward-looking and detached from external human capital, artistic/design concepts and markets. In other words, by the 1990s, JDZ lacked the internal industry diversity (Trippl et al., 2018) to activate new path developments.
JDZ has gradually rejuvenated and renewed its developmental path by enhancing extra-local and global linkages. Since the mid-2000s, JDZ, while only a third-or fourth-tier city within the urban hierarchy of Chinese cities, has attracted large inflows of external creative talent from throughout China and abroad to work in its ceramics industry. These talented individuals are often referred to as 'JDZ drifters' (Jingpiao). In 2018, there were around 30,000 such JDZ drifters (Jingdezhen Porcelain Bureau, 2018). Meanwhile, JDZ's innovation capacity has been enhanced, allowing the cluster to diversify its products significantly. In short, JDZ has become a vibrant, creative cluster over the last two decades (Yang et al., 2021). This paper found that JDZ's revival has largely been driven by the actions of diverse individuals (e.g., transnational and/or migrant artists, entrepreneurs and traders), acting as boundary spanners, who have helped the cluster establish various kinds of extra-local and global linkages. To do so, these individuals first undertook the discursive construction boundary-spanning function to help 'brand' JDZ and increase its national and even global recognition, which in turn attracted significant inflows of external creative talent. After discursive construction, boundary spannersespecially locally based creative talentperformed the innovation promotion function to transfer global, modern artistic and design knowledge into the cluster's 'local buzz'. Afterwards, as producers in JDZbeing equipped with up-to-date external knowledgebecame able to produce a range of creative and innovative products, boundary spanners further performed the market reach function to connect JDZ's producers with external markets and buyers. While boundary-spanning involves multiple and sequential processes, this present study focuses on this market reach dimension. In the context of JDZ, extralocal market linkages largely refer to external but domestic linkages.

Methodology
This exploration of the 'rebirth' of the JDZ cluster is primarily based on qualitative research, most importantly comprising 108 semi-structured interviews conducted with 101 informants (for details, see Appendix A in the supplemental data online) between September 2017 and December 2018. Informants were selected based on non-probability sampling. We tried to ensure that we had a representative sample by carefully choosing interviewees across key axes of differences, such as their places of origin, careers, specialties, and education backgrounds. These interviewees were individuals who either had contributed to, constituted or witnessed the transformation of the cluster, or who had been involved in or had experienced boundary-spanning activities. The informants can be broadly categorized into three types: local actors, including local artisans, artists and entrepreneurs, who tended to be born or educated in JDZ; extra-local actors, including external buyers and traders; and boundary spanners. The last is a functional role: boundary spanners connect 'local' with 'external' actors, and they can hold various jobs, such as artists, gallerists and creative market organizers.
In addition to semi-structured interviews, participant observation was also conducted during various local events such as trade fairs and exhibitions. Participant observation provided additional evidence and contextual understanding which complemented the information collected through interviews. Specifically, this method enabled us to observe the interactions among different actors in real settings, for instance, how boundary spanners helped producers and customers communicate and discuss deals. The qualitative information generated from the interviews (average length 45-90 min) and observations was recorded, transcribed and then coded to categorize the raw data into meaningful themes. This helped depict JDZ's evolutionary story and its key drivers.
While qualitative data were the most accessible in this research context, the study was not able to access much quantitative information due to a lack of published quantitative data regarding JDZ's ceramics industry, such as its export value and domestic sale. There are two reasons for this. First, JDZ's ceramics industry is highly decentralized: it is constituted by thousands of SMEs, and each is small in size and produces various different types of products. Second, the industry is highly informal in terms of its production and sales. Both factors make it very difficult for the government or associations to collect and generate quantitative data. Despite such challenges, some available official 884 Di Wu and Neil M. Coe quantitative data were acquired and used in this research. For instance, JDZ Statistics Yearbooks and Jiangxi Statistics Yearbooks over the past two decades and several official local industry reports provided an overview of JDZ's ceramics industry and its transformation over time.
When analysing the qualitative and quantitative data collected from different methods, the triangulation method (Creswell & Miller, 2000) was further used to ensure the validity of the acquired data, and at the same time to address the weakness inherent in any one single method.

BOUNDARY SPANNERS AND MARKET REACH: ESTABLISHING EXTERNAL MARKET LINKAGES
This section illustrates how individual actors acted as boundary spanners and facilitated JDZ-based producers to better connect with external customers through brokering structural holes and increasing proximity. Boundary spanners may do so through convening quasi-permanent clusters within JDZ, facilitating local producers to attend external events and establishing one-to-one market linkages.

Convening quasi-permanent clusters locally
Before the 2010s, JDZ did not really function as a marketplace for ceramics products. The predominant marketing pattern was local individual traders venturing outside to sell products. There was a lack of external buyers, particularly wholesalers, coming into the cluster to source for products (Fang, 2000). For instance, in 2018, JDZ hosted 224,400 overseas visitors and 49.31 million domestic visitors, while these two figures were only 7,333 and 990,000, respectively, in 2000 (Jiangxi Statistics Bureau, 2001. This made it difficult for producers in JDZ, especially start-up entrepreneurs, to access external buyers. Meanwhile, although JDZ has attracted significant inflows of external creative talent since the mid-2000s, these individuals, who tended to have pre-existing marketing networks with external buyers, did not rely on the market function of JDZ. Instead, JDZ served primarily as a production base for them. To tackle this problem and to bring external buyers into the cluster, some resourceful individuals convened trade fairs, that is, weekly creative markets, in JDZ to provide a flexible platform that enables local producers to 'construct' relationships with external buyers and brokers their structural hole (Burt, 1992). By acting as 'connectors' of relationships, these individual actors can be considered boundary spanners. The first actors performing this boundary-spanning role is a local artist Kai (pseudonym), along with the management team of the Pottery Workshop (PWS). PWS, founded by a renowned ceramist from Hong Kong, is one of the most influential ceramics-art-related organization in JDZ. Since its establishment in 2005, PWS has organized an international artist residency programme that accommodates international artists to create artworks in JDZ, as well as various seminars and exhibitions that encourage these artists to disseminate their knowledge locally.
In 2008, Kai, as an early career local artist who struggled with accessing external buyers herself, persuaded the founder of PWS to convene a flexible, temporary market in JDZ. As such, Kai, in coalition with the management team of PWS, initiated the Saturday PWS creative market. Initially, they aimed to establish a platform whereby new university graduates could reach out to potential buyers, make a living and thereby stay in JDZ. The first creative market thus started in June 2008, since most final-year students from local universities would graduate and leave JDZ at that time because of the lack of jobs or entrepreneurial opportunities locally.
PWS provided free space for this market and helped advertise the event during its weekly seminars among actors involved in the ceramics industry. Kai took charge of inviting local producers to participate as exhibitors. This creative market started with only 20 exhibitors, who were mainly students and graduates from local universities. It initially started as a local exchange fair (Golfetto, 2004); visitors were mainly local residents, other local university students and foreign artists staying in the PWS residency programme. Later, media outlets from JDZ, Jiangxi province and even the national level started to profile the event in mass media such as television programmes and newspapers. The management team of PWS, acting as boundary spanners, also used their own connections to promote this event in various external professional gatherings. Gradually, this event became more externally oriented so that mostly domestic buyers from other cities in China, including both wholesalers/distributors and individual tourists, got to know of it and came to source for, and buy, products.
As the influence of this creative market increased over time, more JDZ-based producers became eager to participate in it as exhibitors. Besides local students and university graduates, many external creative individuals also took part: in 2017, a total of 915 producers participated. Since PWS aims to make it a flagship event showcasing the most innovative and high-standard products in JDZ, it strictly controls the entry into this market to ensure its high standards; only those producers offering original and creative products are selected.
Furthermore, as the PWS creative market alone could not satisfy the increasing demand from exhibitors, three other trade fairs were subsequently started in JDZ by several resourceful and entrepreneurial individuals who functioned as boundary spanners (Table 1). These fairs are run regularly (every week), thereby becoming a quasi-permanent feature of JDZ.
Such trade fairs are particularly important for producers in JDZ, since most of them produce niche, smallbatch products. According to Schuldt and Bathelt (2011), producers making such highly individualized, small-batch products tend to strongly rely on trade fairs to access customers and sell products. This is because trade fairs enable buyers to 'feel, touch, sit in, and experience goods' in order to assess the subtle differences (e.g., in Boundary spanners and the external market reach of clusters: the case of the Jingdezhen ceramics cluster in China quality, feel, workmanship and materials) between different alternatives (Power & Jansson, 2008, p. 431). As such, during these fairs in JDZ, producers and buyers engage in contextualized transactions (Callon, 1998), whereby both parties, through face-to-face interactions, search for interested partners to transact with. Through classic deal-making and follow-up negotiations during these events, many producers have subsequently established long-term, stable customer relations (Bathelt et al., 2017). Thus, for many exhibitors, especially startup artists and entrepreneurs, weekly creative markets have become a significant venue for reaching out to external buyers. For instance, according to one early career entrepreneur: To open your own store, you have to invest a lot in paying the rent, decorating the store, hiring staffs, and so on. However, in creative markets, because of the significant number of buyers visiting it, sometimes the sales on one Saturday morning can be higher than the sales of certain stores for a whole week or even a month. Also, creative markets are more flexible; if I get some stable orders, I can stop attending them for a while and concentrate on production.
(entrepreneur 8, October 2017) Most importantly, the four different fairs in JDZ are interconnected and complementary. For example, one young entrepreneur started with attending the free and self-organized market when his works were still under development.
As his products became more mature and creative over time, he was selected to attend the higher standard PWS creative market (entrepreneur 16, June 2018). Some other producers attend more than one fair to seek more customers (e.g., participating in the Taoxichuan market each Friday and the Mingqingyuan market each Sunday). For Power and Jansson (2008), trade fairs can be conceptualized as cyclical clusters rather than temporary clusters, emphasizing the connectedness of different trade fairs into a continuous cycle of events. While Power and Jansson framed this in terms of trade fairs occurring in different places, the four fairs in JDZ also compose such a cycle, which is important for producers to reach external buyers. Moreover, in an extreme situation, global buzz can become a permanent phenomenon of a place, continuously attracting talent and developing into a global hub of diverse knowledge pools (Bathelt & Schuldt, 2010). The creative markets in JDZ similarly created such a quasi-permanent cluster, blurring the boundary between the 'global buzz' of trade fairs and the 'local buzz' of permanent clusters. These events thus not only provide platforms for producers to access external buyers, but also have wider spillover impacts on the cluster as a whole. After developing stable customer bases through creative markets, many entrepreneurs go on to expand their production capacity and run their own stores. Consequently, other parts of JDZ also transformed into ceramics marketplaces. For example, a former state-owned factory, the Sculpture Factory, where the PWS creative market and the Mingqingyuan creative market locate, has been transformed from a rundown space into a dynamic area where hundreds of ceramics shops are concentrated. Thus, when these temporary clusters become a quasi-permanent phenomenon of a cluster, external buyers would frequently and regularly visit the cluster to source for, and buy new products, and the cluster as a whole in turn becomes a recognized marketplace within the relevant industry.

Facilitating participation in external temporary clusters
In addition to convening quasi-permanent clusters locally to attract external buyers inwards, some resourceful individuals further facilitated JDZ-based producers to attend external (both domestic and international) temporary clusters such as trade fairs and exhibitions. In this process, as will be explained shortly, these individuals, acting as both 'connectors' and 'communicators' between local producers and external event organizers, can be considered boundary spanners as well. There are two types of individual actors performing this function. The first type is professional traders, art dealers or gallerists, who make a profit through this boundary-spanning practice and charge a commission fee. These individuals have dense connections with external event organizers and are aware of their needs. Meanwhile, they have close contacts with and good knowledge of JDZ's producers. As such, they are well positioned to broker the structural hole (Burt, 1992) between these two parties. For instance, Yiwei (pseudonym), a curator and art dealer, helped local producers access and attend external exhibitions and thus acted as a boundary spanner. She was born in JDZ and, after university study, she worked in a media agency in Beijing for two years. During this period, she developed a good rapport with event organizers all over China. She returned to JDZ in 2010 to work for a ceramics journal for four years, during which time she built up good connections with many JDZ-based artists. She has been running her own business on modern ceramics artworks and design products since 2014. She works closely with around 30 mostly early career artists in JDZ. Using her connections with event organizers and exhibition curators, she has been promoting these artists' works actively. In her words: There are many good artists and designers in JDZ. But they don't have access to external buyers and curators. … Each individual artist is like a pearl, and what I do is to assemble these individual pearls into a pearl necklace and present to other people.
(gallerist 5, October 2018) These events usually do not have open application processes; rather, the selection of participants tends to be done through personal networks. Since event organizers tend to have limited, imperfect knowledge regarding appropriately talented artists, when there are exhibition opportunities, Yiwei, as a boundary spanner, plays a 'curating' role by selecting and recommending different artists according to the theme and characteristic of the event. In other words, Yiwei helps JDZ-based producers access external temporary clusters, by brokering the structural hole between producers and event organizers and helping producers overcome the substantial challenges of 'self-discovery' (Saxenian & Sabel, 2008), the process by which an entrepreneur decides which markets to serve. The other type of boundary spanners is artists, designers or entrepreneurs. In contrast to professional traders or art dealers, the primary motivation of artists and entrepreneurs to perform this role is not for profit. Rather, since workers in creative industries tend to have precarious careers, mutual support practices such as sharing work opportunities tend to be a common phenomenon (Scott, 1998). Accordingly, artists and entrepreneurs in JDZ have formed close-knit communities of practice (Wenger, 1998) involving both local actors and external creative talent. While many existing studies have extensively showed how communities of practice foster knowledge creation and diffusion (Amin & Cohendet, 2004;Cohendet et al., 2014), this research finds that they are also important for providing mutual support in the marketing and sales realm.
For some producers in JDZ, especially those at the start-up stage and therefore with less connections, attending external temporary clusters can be a difficult task, involving considerable uncertainty and requiring a large investment of both time and money. While the literature has clearly identified the benefits of attending temporary clusters in terms of sales and marketing, most of these studies take for granted entry into these events and pay relatively little attention to the difficulties and challenges producers may face in accessing them.
Indeed, many influential trade fairs and exhibitions in the arts and design industry have high entry barriers and only invited participants can attend (Power & Jansson, 2008). In these circumstances, more established external creative individuals often function as boundary spanners by sharing their opportunities with other artists and designers in JDZ, or by using their own reputation as the basis for introducing others to attend these events.
Fei (pseudonym) is one such case. He came to JDZ in 2013 to run his own design studio. He has won various design awards and became considered a 'star' designer. He often helped his JDZ-based peer artists attend highend fairs and exhibitions. He gave one example: In June 2018, I was invited to attend an exhibition in Japan. Because I was given a large exhibition space, I also invited two other friends from JDZ to showcase their works. We make different products and our products are complementary. By inviting them, it makes the exhibition space more attractive and have better visual effects.
(entrepreneur 20, July 2018) Moreover, there are numerous trade fairs and exhibitions that JDZ's producers can potentially target. Besides the issue of access, many producers do not have sufficient knowledge of these various fairs. Since attending these events can be a costly investment, producers find it difficult to decide which event to attend. After attending different professional events frequently and gaining abundant knowledge of such events, many artists and entrepreneurs behave as knowledge gatekeepers (Giuliani, 2011;Graf, 2010) through sharing their experience and knowledgesuch as these events' outcome in terms of sales, contacts and media exposureto other producers. These experienced individuals can thus also be considered boundary spanners. However, this sharing tends to happen only within enclosed, close-knit communities of practice, as part of the mutual support and reciprocity among members. Hence, this practice only benefits selective producers in a cluster as a 'club good' (Morrison, 2008).

Establishing one-to-one market linkages
Temporary clusters connect producers and buyers in a many-to-many form. Additionally, some resourceful individualsincluding both professional traders/art dealers and artists/entrepreneurshelp establish one-to-one market relations through inter-personal, social networks. They both construct and coordinate such market relations and thus function as boundary spanners. First, boundary spanners link external buyers with JDZ-based producers for final products. Section 5.1 detailed the establishments of creative markets locally. Since the key value of products in design-intensive industries tends to be symbolic, during these events, producers can quickly obtain inspirations for new products (Asheim & Gertler, 2005). Such unintended knowledge spillovers have however discouraged some producers, especially those established ones with stable customer relationships, from participating in such 'public' markets in JDZ, in order to protect their intellectual property rights. As such, in JDZ, besides 'public' markets, there also exist more exclusive 'private' markets.
To enable external buyers to access the private markets in JDZ, some individuals functioned as boundary spanners not only in helping buyers search for appropriate partners, but also through facilitating contract fulfilments in the case of complex transactions (cf. Kapur & McHale, 2005). For example, Luo (pseudonym), a trader and a gallery operator, performed this role and thereby acted as a boundary spanner. After graduating from the JDZ Ceramics University, he went to Shenzhen to work as a graphic designer in 2002, and returned to JDZ in 2015 to operate a gallery. Through his alumni networks and convening frequent events in his gallery, he established abundant connections with many established designers in JDZ specializing in different products. Luo explained why his boundary-spanning role is important: There are many external wholesalers, who demand a wide range of ceramics products. The characteristic of JDZ is that most producers have small-scale production and thus one individual producer cannot meet buyers' demands in term of the variety of products. Buyers thus need to source products from many designers. But designers are scattered in JDZ and many don't display their works in public markets, which makes it very difficult and time-consuming for external buyers to access designers.
(gallerist 3, July 2018) According to the buyer's specific demand in terms of style and production capacity, Luo would first 'match' designers and buyers to construct networks between them and broker across structural holes (Burt, 1992). For instance, Luo provided buyers with the portfolios of potential designers to let them have a first-round selection and, if buyers show interest, Luo often invited them to visit JDZ and organized designer studio trips to enable them to communicate with designers personally. During such visits, more importantly, Luo coordinated their networks to facilitate and encourage their communication and transactions. Specifically, he both introduced the buyer's needs and sales channels to the designer, and explained the designer's product characteristics, specialities and past exhibition experiences to the buyer. This helped increase their social and cognitive proximity (Boschma, 2005). Boundary spanners are also important for constructing and coordinating subcontracting relations between local artisans and external customers such as artists, designers, and entrepreneurs. In this process, selecting highly skilled subcontractors that can match the specific needs of external customers is required in the first place. Some individual actors possess abundant local industrial knowledge for example, knowledge of ceramics-making techniques and a portfolio of local artisansthat most external customers often lack. This knowledge is crucial: because of the high level of vertical disintegration of production in the industry, highly skilled artisans in different production processes tend to belong to different workshops in JDZ. As such, individuals embodied with such industrial knowledge could function as boundary spanners to help external customers identify and access capable local subcontractors and thereby facilitate the construction of market relationships.
Furthermore, boundary spanners help coordinate market networks. On the one hand, they can increase the cognitive proximity between local subcontractors and external customers by reducing the knowledge gaps between them. Many external customers, such as traditional Chinese painting painters and graphic designers, are not familiar with ceramic materials. Their knowledge bases are more symbolic (arts-based), while local artisans tend to have synthetic (engineering-based) knowledge bases (Asheim & Hansen, 2009). For example, according to one gallerist who functioned in such boundary-spanning roles: I have seen many creative design proposals, which are unrealistic to be made in ceramics, because these designers don't understand the characteristics and techniques of ceramics and the limitations posed by the material. Sometimes I need to 'protect' the local artisans by explaining to the designers that it's not the fault of these artisans but a problem with the ceramic material. Sometimes I discuss with the designers how to adjust their designs to be feasible for ceramics.
(gallerist 1, November 2018) On the other hand, boundary spanners mediate different cultural barriers between subcontractors and their customers to increase their social proximity. As Bathelt et al. (2018)  Even for many Chinese customers, there are also evident cultural differences. For example, one artist from Guangzhou complained that: 'The local culture is that you cannot command local artisans to do things. You need to treat them like friends rather than workers, which is very different to what I had been used to' (artist 3, June 2018). To overcome these cultural differences, boundary spanners first translate (Reinecke et al., 2018) between the two parties to encourage them to recognize each other's values, standards and expectations through engaging in frequent conversations. Second, boundary spanners buffer (Palus et al., 2014) between them to keep reminding both parties what has been agreed in the contract, to ensure that neither party is being taken advantage of. Specifically, if one party (either the customer or the subcontractor) deviates, boundary spanners intervene to push the discordant party and comfort the other party. At the same time, boundary spanners guide local subcontractors to adapt their way of working and improve their standards, which is important for the long-term coupling with external customers.

CONCLUSIONS
To provide a fuller understanding of cluster development in the market realm, this study developed further the 'market reach' boundary-spanning function identified in Wu's (2022) framework. This paper identified three market reach mechanismsconvening quasi-permanent clusters locally, facilitating participation in external temporary clusters and establishing one-to-one market linkagesthrough which resourceful individual actors, functioning as boundary spanners, connect clusters to external markets. Being equipped with abundant market knowledge and information, boundary spanners are able to help address two major obstacles that producers from a cluster often encounter in terms of accessing and transacting with external buyers. First, boundary spanners are embodied with information regarding capable producers from a cluster and reliable external buyers; with such information, boundary spanners can match them up and help them construct connections through brokering the structural holes between them. Second, boundary spanners are embodied with knowledge regarding heterogeneous business cultures, habits and knowledge bases; with such knowledge, they help increase the social and cognitive proximity between local producers and external buyers to coordinate their relationships so that their communication and transactions can take place more smoothly and effectively.
More broadly, this study aims to contribute to the cluster literature in two interrelated ways. First, it unpacks the concrete processes through which clusters' extra-local market linkages get constructed and coordinated through the agency of individual actors. Second, and more specifically, bridging the literatures on temporary and permanent clusters, it unpacks the dynamic relationship between these two kinds of clusters and shows how temporary clusters, while being short-lived events, enable permanent clusters to forge extra-local market linkages and in turn bring lasting impacts on their development. For instance, if influential temporary clusters are being held in a cluster regularly and consistently, hence becoming a quasi-permanent phenomenon of the cluster, they may contribute to the construction of the marketplace function of the cluster more generally. In short, this study identifies the co-evolution processes of the establishment of local firms' external market linkages, the development of temporary clusters, and the growth of permanent clusters.
This analysis, however, is based on a case study of the JDZ ceramics cluster, and thereby the market reach mechanisms identified in this research are informed by the activities that boundary spanners perform in the context of a creative industry characterized by niche, design-intensive, individualized and small-batch production. The extent to which this study's findings apply to other industries and what the market reach mechanisms in more general might be, deserves scrutinizing in future research. Furthermore, future research could pay more attention to investigating the complex interrelationships between the various dimensions of the external connections of clusters. For example, whether and how the establishment of extra-local market linkages influence a cluster's production and knowledge linkages, and vice versa, could be a potential topic for future research.
This study may also bear some policy implications. It shows that temporary clusters such as trade fairs are fundamental instruments in enabling market reach. Moreover, this study identifies the key roles of individual boundary spanners in facilitating firms to access external buyers through these events. As such, for local governments to better connect their local firms with external markets, they should not only invest in convening temporary clusters locally or supporting local firms to attend such events externally. More importantly, they could draw more support from resourceful individual actors (primarily returnees and transnational, mobile individuals) in the relevant industry, such as renowned artists, entrepreneurs, and scientists, and encourage them to use their own connections and market knowledge/information to maximize the value of temporary clusters in sales and market construction. As such, when designing policies in relation to clusters and temporary clusters, more attention could be paid to involving resourceful individual actors and mobilizing their power and networks. The challenge in policy terms is thus how best to harness and steer boundaryspanning dynamics that, in the case of JDZ in this paper, have largely been bottom-up and organic in nature.