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.
All Japan Pro Wrestling
Some interpromotional activities that would not have happened under Shohei Baba's watch have taken place, including the previously unfathomable IWGP Heavyweight Champion vs. Triple Crown Heavyweight Champion bout on a New Japan Pro Wrestling event on February 20, 2005; Satoshi Kojima (who was the Triple Crown Heavyweight Champion) defeated Hiroyoshi Tenzan for the IWGP Heavyweight Championship, which made Kojima the only wrestler to ever hold both titles simultaneously to that point (Keiji Mutoh would later accomplish the feat in 2008. However, he would hold the IWGP Championship as Keiji Mutoh, and the Triple Crown Championship as his alter-ego The Great Muta) In addition, Keiji Mutoh and Satoshi Kojima are both New Japan Pro Wrestling alumni but played a consistent role in the main event picture of All Japan Pro Wrestling from the time of their arrival to the promotion. Furthermore, Keiji Mutoh competed at a Pro Wrestling Noah event on July 10, 2004, teaming with fellow AJPW wrestler Taiyō Kea to face Mitsuharu Misawa and Yoshinari Ogawa. On July 18, 2004, Mitsuharu Misawa returned to All Japan and defeated Satoshi Kojima at "Battle Banquet". Misawa returned to All Japan again on October 31, 2004 for the "Keiji Mutoh: Love and Bump" pay-per-view event, where he (along with Keiji Mutoh) defeated Hiroshi Hase and Kensuke Sasaki in what was billed as a "Special Dream Tag Match".