This chapter analyses the role of regional networks in the sumo world and factors influencing labour supply. During the high-growth period, junior high school graduates called ‘golden eggs’ participated in mass employment migration to urban areas, with the sumo world experiencing similar phenomena. Concentrated recruitment from specific regions to particular sumo stables indicates the existence of regional networks. Successful senior wrestlers’ achievements created chain effects encouraging junior wrestlers to join. Additionally, rural adverse weather conditions (such as cold damage) reduced agricultural income, consequently increasing sumo recruitment. This demonstrates how economic hardship motivated sumo entrance. Communal living in sumo stables strengthened hometown bonds, functioning as information networks. These networks compensated for market imperfections, enhancing labour market efficiency. Data analysis confirms that poor harvest years correlated with increased recruitment the following year, demonstrating the sumo labour market’s sensitivity to economic conditions. The chapter reveals how informal networks played crucial roles in traditional Japanese society’s labour allocation mechanisms, providing insights into how social capital facilitates economic transactions.