Nihon Ki-in professional, pupil of Takabayashi Takuji
1p: 2015, 2p: 2017-01-01, 3p: 2018-01-01, 4p: 2019-01-01, 5p: 2020-01-09, 6p: 2021-01-07, 7p: 2022-01-01.
(Note the dates; he was promoted each year by end-of-year money rankings.)
- 2018: Winner of the Kido Prize for best winning streak (14 games)
- 2018: Runner up in the 13th Wakagoi, losing to Fujita Akihiko
- 2019: Runner up in the 44th Shinjin O, losing to Son Makoto
- 2022: Runner up in the 17th Wakagoi, losing to Ueno Asami
In 2022, he achieved another remarkable winning streak, 13 games.
Koike was seeded into the second round the of 2022 Shinjin O. He beat Imabun Taro, Sakai Kentaro and Oomote Takuto before losing to Sakai Yuki in the semi-final.
On Fox he plays as hiro120.