Overview
The free agent (FA) system grants a player whose first-team registration has reached a set number of seasons the right to choose his next club without his current team's consent; NPB adopted it in the 1993 offseason. The right does not take effect automatically: a qualified player must declare free agency within the designated window, and only then can he negotiate with other clubs. There are two types of rights. Domestic FA covers negotiation with NPB clubs, while international FA extends to clubs overseas, including Major League Baseball. Declaring is not the same as leaving: players who declare and then re-sign with their original team, and players who hold the qualification but never declare, are both common.
Qualification and compensation
Qualification is counted in first-team registration days. A season with 145 or more days of registration counts as one season, and years that fall short are pooled day by day, though days beyond 145 do not carry over. Domestic FA rights take eight cumulative seasons, shortened to seven for players who entered through the draft in 2007 or later out of a university or a corporate-league team; international FA rights take nine. Once either right is exercised, reaching the next declaration takes four more seasons. Transfers come with compensation. Players are ranked by salary among the Japanese players of the club they are leaving: the top three are rank A, fourth through tenth rank B, and eleventh or below rank C. When a rank A or B player moves, the former club receives money, or money plus one player chosen from outside a list the signing club has protected in advance; rank C moves require no compensation. A club can sign at most two FA players in the same offseason, and rank C players do not count toward that limit. This framework follows the players association's explanation (as of September 2010) and is understood to have stayed in place since; details can change with each offseason's agreements, so the current year's rules and official notices are the surest place to confirm (as of 2026).
History and debate
In the system's first offseason in 1993, Hiromi Matsunaga moved from Hanshin to Daiei and Hiromitsu Ochiai from Chunichi to Yomiuri, and exercises of the right by stars such as Kazuhiro Kiyohara and Kimiyasu Kudo have kept redrawing the league's balance of power. More recently, the moves of Yoshihiro Maru (2018 offseason, Hiroshima to Yomiuri) and Hotaka Yamakawa (2023 offseason, Seibu to SoftBank) drew wide attention. While free agency greatly expanded players' rights, the concentration of talent in wealthier clubs and cases where established players are lost through the player-compensation mechanism remain points of debate.