Kai Ishizawa has two losses against one opponent on his boxing record. For a list of Ishizawa's best fights, refer to "Best fights of Kai Ishizawa".
On April 22, 2022 Kai Ishizawa fought Masataka Taniguchi in a strawweight world-title fight for Taniguchi's WBO title. Ishizawa was 25 years old and with a record of 10-2 (9), and Taniguchi was 28 years old and with a record of 15-3 (10). Ishizawa lost the fight via 11th-round TKO.
On September 21, 2019 Kai Ishizawa faced off against Masataka Taniguchi at age 22. He was coming in with a record of 6-1 (6), and Taniguchi was 25 years old and with a record of 11-3 (7). Ishizawa lost the fight via 8-round unanimous decision.