Japanese-style baseball

Rubber-ball baseball (Japanese: 軟式野球, romanized: nanshiki yakyū), also known as Japanese-style baseball, is a variant of baseball developed in Japan that uses a hollow rubber ball instead of a standard leather baseball. In English, it is also referred to as nankyu baseball, nanshiki baseball, or simply rubber baseball.

Rubber-ball baseball uses a hollow rubber ball that differs significantly from a standard baseball in elasticity and weight, which affects playing style, equipment, and player technique. Apart from the ball, the rules are largely the same as those of conventional baseball. By contrast, the ball used in softball is typically leather-covered but larger than a standard baseball.

The term may refer specifically to baseball played with a hollow rubber ball, or more broadly to variants in which the outer layer of a standard baseball is replaced with rubber.

It is widely played in Japan by children and adults, including both men and women.