Yūsei Koga

Yūsei Koga (古賀 悠聖, Koga Yūsei, January 1, 2001) is a Japanese professional shogi player ranked 6-dan.

Yūsei Koga
Native name	古賀悠聖
Born	(2001-01-01) January 1, 2001 (age 24)
Hometown	Fukuoka, Japan
Career
Achieved professional status	October 1, 2020(2020-10-01) (aged 19)
Badge Number	326
Rank	6-dan
Teacher	Isao Nakata (8-dan)
Meijin class	B2
Ryūō class	6
Websites
JSA profile page

Early life and apprentice professional

Koga was born in Fukuoka, Japan on February 13, 1996.^[1] He learned how to play shogi from his grandfather when he was about four years old.^[2][3]

Koga entered the Japan Shogi Association's apprentice school in September 2011 as a protegee of shogi professional Isao Nakata.^[2][3] He was promoted to the rank of apprentice professional 3-dan in April 2017 and obtained full professional status and the rank of 4-dan after finishing third in the 67th 3-dan League (April 2020 – September 2020) with a record of 13 wins and 5 losses.^[2][3][4][5] Although Koga's third place finish was not sufficient to earn him direct promotion to 4-dan, it was good enough to earn him a second promotion point which gave him the option to enter the professional ranks as a free class player. After consulting with his mentor Nakata, Koga decided he wanted to turn professional even if it meant starting in the Free Class.^[2][3][a]

Shogi professional

In September 2021, Koga was promoted to Meijin Class C2 after defeating Hirotaka Kajiura 7-dan to reach the finals of the 52nd Shinjin-Ō [ja] tournament. Koga's victory meant that he satisfied the criteria for promotion to Class C2 for the 80th Meijin League (April 2022 – March 2023).^[7][8]

Promotion history

The promotion history for Koga is as follows.^[9]

• 6-kyū: September 2011
• 3-dan: April 2017
• 4-dan: October 1, 2020
• 5-dan: March 14, 2023
• 6-dan: March 5, 2024

Tsume Shogi Solving Competition

In March 2024, Koga won the 21st Tsume Shogi Solving Competition. He finished with a score of 73 points out of a possible 100 to win the competition for the first time. The tournament had been last held in 2019, but was cancelled from 2020 to 2023 due to the COVID-19 pandemic. Sōta Fujii 8-crown title holder, who won the competition the last five times it was held, did not participate in the competition.^[10]

Notes

1. Koga earned his first promotion point in third place with a record of 13 wins and 5 losses in the 65th 3-dan League (April 2019 – September 2019).^[3][6]