Shiro Koshinaka
Upon returning to New Japan in 1987, Kobayashi won the vacated IWGP Junior Heavyweight Championship on August 20, by defeating Nobuhiko Takada in a tournament final, successfully defending it against the likes of Shiro Koshinaka, Owen Hart, Keiichi Yamada and Takada. He held the title until December 27, losing it to the debuting Hiroshi Hase. In 1988, he had numerous encounters with Shiro Koshinaka over the IWGP Junior Junior Championship, but he came up short on retrieving what was once his. In spite of rivaling with the champion, he and Koshinaka started to team up in tag team and six-man matches. In April 1989, he served as the first opponent of Jyushin Liger (Keiichi Yamada's first match under the Liger persona), in a losing effort at the Tokyo Dome. In 1990, he moved up to the heavyweight division, and joined the New Japan Sekigun against the Blond Outlaws. In 1992, he and Shiro Koshinaka formed the Heisei Ishingun, while feuding with two karatecas in Masashi Aoyagi and Akitoshi Saito.