List of Japanese players in Major League Baseball

A total of 54 Japanese-born players have played in at least one Major League Baseball (MLB) game. Of these players, eight are currently on MLB rosters. The first instance of a Japanese-born player playing in MLB occurred in 1964, when the Nankai Hawks, a Nippon Professional Baseball (NPB) team, sent three exchange prospects to the United States to gain experience in MLB's minor league system. One of the players, pitcher Masanori Murakami, was named the California League Rookie of the Year while playing for the Fresno Giants (the San Francisco Giants' Class-A team). Giants executives were impressed with his talent and on September 1, 1964 Murakami was promoted, thus becoming the first Japanese player to play in MLB. After Murakami put up good pitching statistics as a reliever, Giants executives sought to exercise a clause in their contract with the Hawks that, they claimed, allowed them to buy up an exchange prospect's contract. NPB officials objected, stating that they had no intention of selling Murakami's contract to the Giants and telling them that Murakami was merely on loan for the 1964 season. After a two-month stalemate the Giants eventually agreed to send Murakami back to the Hawks after the 1965 season. This affair led to the 1967 United States – Japanese Player Contract Agreement, also known as the "Working Agreement", between MLB and NPB, which was basically a hands-off policy.

For thirty years Murakami was the only Japanese player to appear in an MLB game. Pitcher Hideo Nomo, with the help of agent Don Nomura, became the second Japanese-born player to play in MLB in 1995. Nomo, who was not yet eligible for free agency in Japan, was advised by Nomura that a "voluntary retirement" clause in the Working Agreement did not specify that a player wishing to play again after retiring must return to NPB. Nomo utilized this loophole to void his NPB contract with the Kintetsu Buffaloes and play in MLB. He announced his retirement from NPB in late 1994 and signed with the Los Angeles Dodgers in February 1995. Nomo's maneuver and Hideki Irabu's later MLB contractual complications were contributing factors to a major revision of the Working Agreement in 1998 that created the current posting system. Since its inception 12 Japanese-born players have been signed through the system, however one of these players, Shinji Mori, did not play in a single MLB game due to an injury. NPB players who have nine or more years of playing service with NPB can become free agents and do not need to enter MLB through the posting system. The remaining Japanese-born players that have played in MLB have either signed as free agents or signed as amateur players. Mac Suzuki, Micheal Nakamura, Kazuhito Tadano, and Junichi Tazawa are the only Japanese players to have debuted in MLB without previously playing in NPB.

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