Naomichi Marufuji
Kotoge's heavyweight debut took place on January 7, 2017, when he and Naomichi Marufuji unsuccessfully challenged Go Shiozaki and Maybach Taniguchi for the GHC Tag Team Championship. The following day, Kotoge defeated Rionne Fujiwara for his first win as a heavyweight. Momo no Seishun Tag formally disbanded on February 14, after Kotoge defeated Harada in a singles match. In May, Kotoge and Go Shiozaki advanced to the finals of the 2017 Global Tag League, after finishing their block with a record of five wins and two losses. On May 4, they were defeated in the finals of the tournament by reigning GHC Tag Team Champions Maybach Taniguchi and Naomichi Marufuji. On June 4, Kotoge defeated Kenoh to become the number one contender to the GHC Heavyweight Championship. Kotoge received his title shot on June 25, but was defeated by Katsuhiko Nakajima.