This chapter analyses the Sumo Association’s responses to foreign wrestler increase and institutional reform impacts. During the 2000s, consecutive foreign yokozuna and Japanese yokozuna absence caused sumo popularity decline. Consequently, the Sumo Association introduced quota systems limiting foreign wrestler numbers. Additionally, match-fixing scandals prompted rigorous punishment. Public injury system abolition increased injured wrestlers’ absences. Data analysis reveals these institutional reforms impacted Japanese and foreign wrestler performance differently. Match-fixing elimination strengthened meritocracy but simultaneously increased wrestler burdens. Strategic absences increased, representing unintended reform consequences. In 2025, a young Japanese yokozuna emerged for the first time in 20 years, reviving sumo popularity in what is termed the ‘Sumo Renaissance’. Institutional reforms caused short-term confusion but contributed to long-term sumo world improvement. The young Ukrainian-born yokozuna candidate’s emergence symbolizes a new era. Balancing globalisation and Japanese values is being explored. The chapter demonstrates how regulatory interventions in traditional institutions produce both intended and unintended consequences, offering insights into institutional reform complexities and cultural preservation challenges in globalized contexts.