[2] He entered into the Japan Shogi Association's apprentice school at the rank of 6-kyū as a student of shogi professional Keita Inoue in September 2004 and obtained professional status and the rank of 4-dan in April 2010 after winning the 46th 3-dan League (October 2009 – March 2010) with a record of 15 wins and 3 losses.
[4] In October 2015, Sugai defeated apprentice shogi professional 3-dan Takahiro Ōhashi 2 games to 1 to win the 46th Shinjin-Ō [ja] tournament for players ranked 6-dan or lower.
[7] In December 2021, Sugai defeated Akira Watanabe to win the 29th Ginga Tournament [ja] for the first time.
[8][a] A few months later in February 2022, he defeated Akira Inaba to win the 15th Asahi Cup [ja], also for the first time.
[12] His good form, however, did not continue and he lost the 73rd Ōshō title match (January – February 2024) 4 games to none.