The Japanese Baseball League (日本野球連盟, Nihon Yakyū Renmei) was a professional baseball league in Japan which operated from 1936 to 1949, before reorganizing in 1950 as Nippon Professional Baseball. The league's dominant team was Tokyo Kyojin (renamed the Yomiuri Giants in 1947), which won nine league championships, including six in a row from 1938 to 1943, when many of Japan's best players were serving in the Imperial Japanese Army.