[11] He won the fight by a first-round knockout, after knocking Chiba down three times by the 1:59 minute mark of the opening round.
[17] He won the fight by a first-round technical knockout, forcing the referee to step in with a flurry of punches at the 2:00 minute mark.
He utilized his height and reach advantage to win the fight by unanimous decision, with all three judges awarding him the first and the second round on their scorecards.
[20] Ryusei faced Mehdi Jraifi, the first foreign opponent of his career, in a non-title bout at KNOCK OUT 2022 vol.3 on April 17, 2022.
[23] He won the fight by a third-round knockout, stopping Kaishi with a combination of a left hook and a flying knee.
[29] Ryusei was expected to face Yodkitsada Yuthachonburi at KNOCK OUT 2023 SUPER BOUT BLAZE on March 5, 2023.
[30] Yodkitsada withdrew on February 8 and was replaced by the Rajadamnern Stadium super bantamweight champion Petchsansab SorJor Tongprajin.
[40] Ryusei was scheduled to face Kotaro Yamada at KNOCK OUT 2024 SUPER BOUT BLAZE on June 23, 2024.
[41] Yamada was replaced by Taimu Hisai due to injury and the bout was turned into a title fight for the inaugural Super Featherweight belt.
[43] Ryusei vacanted the KNOCK OUT Black Featherweight title on 11 July 2024 in order to move up in weight.
[44] Ryusei faced Braian Gavio for the vacant ISKA K-1 World Super Featherweight title at KNOCK OUT K.O CLIMAX 2024 on December 30, 2024.