Champion Carnival
From 1959 to 1972, the Japan Pro Wrestling Alliance (JWA), run by Rikidōzan, held a tournament called World League (also known as the "World Big League"), which featured both Japanese and foreign professional wrestlers. Rikidōzan himself dominated the annual tournament early on, however, after his death in 1963, the tournament was won six times by Giant Baba and once by Antonio Inoki. JWA folded shortly after both Baba and Inoki left the promotion to create All Japan Pro Wrestling (AJPW) and New Japan Pro-Wrestling (NJPW), respectively. Both men took the concept of World League with them to their new promotions, with Baba creating the "Champion Carnival" in 1973 and Inoki creating the World League in 1974, later renaming it G1 Climax.
Japan Pro-Wrestling
In August 1984, Riki Choshu had formed Ishin Gundan with Animal Hamaguchi, Isamu Teranishi, Yoshiaki Yatsu, Masa Saito and Kuniaki Kobayashi to feud with Antonio Inoki and New Japan Pro Wrestling. However, just as the feud was heating up, tensions both in and out of the ring forced Ishingun and a few others to leave NJPW that September. The next month, they formed Japan Pro-Wrestling and also announced a co-promotion with All Japan Pro Wrestling. Masa Saito briefly went back to North America but returned to Japan in 1985 and joined in the new promotion.