After enjoying only demonstration status at several Olympics, baseball was finally embraced as a medal sport at Barcelona 1996, but was dropped from the programme after Beijing 2008.
Baseball for men and softball for women will return for Tokyo.
Given its billing as 'America's pastime', Olympic baseball has surprisingly been dominated by Cuba, which has won three golds and two silvers in five appearances.
United States has won just once and traditionally has not fielded a full-strength Major League Baseball team, relying on college or minor league players previously. That indifference was a factor in baseball's disappearance from the last two Games.
Japan has won silver and two bronze medals, and can be expected to challenge strongly at its home tournament.
New Zealand has never qualified for Olympic baseball and will not compete at Tokyo.