DEEP KICK Jin was scheduled to fight
Tatsuya Tsubakihara during Hoost Cup Kings Kyoto 2. Tsubakihara won the fight by unanimous decision. In 2017 he made his
RIZIN debut against Issei Ishii. Mandokoro won the fight by majority decision. He re-matched
Issei Ishii at KNOCK OUT's Summer FES event. Ishii won the fight by unanimous decision. In November 2018, at J-FIGHT, he fought Shota Toyama. Mandokoro won the fight by decision.
RISE He was given a chance to fight for the RISE 53 kg title at RISE 132, held at the time by
Toki Tamaru. Tamaru won the fight by unanimous decision. Afterwards, he fought Senga at DEEP☆KICK, and once again dropped a unanimous decision. He fought Koki Osaki during RISE 135, and won the bout by unanimous decision. He won his second in a row against Kyosuke, winning by a first round KO. Mandokoro was scheduled to fight
Kazuki Osaki during RISE 139. The fight was later cancelled due to the
COVID-19 pandemic. The fight was subsequently rescheduled for RISE 140. Osaki won the fight by majority decision. Mandokoro is scheduled to fight Syuto Sato during
Rizin 25. He won the fight by unanimous decision. During the Kyushu Professional Kickboxing vol.2 event, Mandokoro fought Tatsuya Hibata for the WBKF World Super Flyweight title. He won the fight by a third-round TKO. Mandokoro was scheduled to fight Soma Tameda at RISE on
ABEMA 2. The bout was a qualifier for the RISE Dead or Alive Tournament. Mandokoro won by a first round knockout. After qualifying for the tournament, Mandokoro was scheduled to fight
Toki Tamaru in the quarterfinals of the 2021 RISE Dead or Alive 53kg Tournament. He won the fight by unanimous decision. Advancing to the semifinals, Mandokoro was scheduled to face
Kazane. Madokoro lost the fight by majority decision. Mandokoro was scheduled to face Yu Hiramatsu at
Rizin Trigger 1 on November 28, 2021. He won the fight by a second-round knockout. Mandokoro was booked to face Syuto Sato at
Rizin 34 – Osaka on March 20, 2022. The fight ended as a no contest after Sato injured his ankle in the first round. Mandokoro faced the third ranked RISE super flyweight contender
Ryu Hanaoka at RISE 161 on August 28, 2022. He lost the fight by a third-round technical knockout, due to doctor stoppage. Mandokoro faced
Koudai Hirayama at RISE 163 on December 10, 2022. He won the fight by unanimous decision, with all three judges scoring the bout 30–29 in his favor. Mandokoro faced
Kazane Nagai in a rematch at
RISE World Series 2023 - 1st Round on July 2, 2023, in a -54 kg World Series reserve bout. He won the fight by
split decision, after an extra fourth round was contested. Mandokoro faced Ruben Seoane at
RISE World Series 2023 - 2nd Round on August 26, 2023, once again in a -54 kg World Series reserve bout. He won the fight by a second-round technical knockout, after thrice knocking Seoane down. Mandokoro took part in the RISE New Warriors Tournament, held at
RISE 173 on November 18, 2023, and faced former opponent
Ryu Hanaoka in the semifinals of the one-day tournament. Mandokoro was able to avenge his loss to Hanaoka, as he won the fight by a first-round knockout, and advanced to the finals, where he faced
Kaito Hasegawa. Mandokoro captured the tournament title, as well as the right to challenge RISE Super Flyweight champion
Kazuki Osaki, by unanimous decision. Mandokoro challenged Kazuki Osaki for the RISE Super Flyweight title at
RISE WORLD SERIES 2024 OSAKA on June 15, 2024. He lost the fight by unanimous decision, with two scorecards of 50–47 and one scorecard of 49–47 in his favor. Mandokoro faced
Ryu Hanaoka for the vacant
RISE Super Flyweight (-53 kg) title at
RISE 184 on December 15, 2024. He lost the fight by unanimous decision. Mandokoro faced the first-ranked RISE flyweight
Riku Kazushima in a super flyweight bout at
RISE Fire Ball on May 11, 2025. He won the fight by split decision, with scores of 30—29, 30—29 and 29—30. Mandokoro faced the
RISE Flyweight champion Ryujin Nasukawa in a super flyweight bout at
RISE WORLD SERIES 2025 Tokyo on August 2, 2025. He lost the fight by unanimous decision. Mandokoro faced Shuri Sakayori at
RISE 194 on December 14, 2025. He won the fight by a second-round knockout. == Championships and accomplishments==