Ginjiro Shigeoka

Shigeoka was scheduled to make his professional debut against Sanchai Yotboon on September 25, 2018. He won the fight by a third-round technical knockout.[4] Shigeoka was awarded the East Japan Boxing Association September MVP award for this victory.[5]

Shigeoka was scheduled to face Gerttipong Kumsahwat on February 26, 2019. He won the fight by a first-round knockout, needing a little over a minute and a half to finish his opponent.[6] Shigeoka was next scheduled to fight Joel Lino on April 14, 2019. He extended his winning streak to three fights with a unanimous decision victory.[7]

Shigeoka was scheduled to face Clyde Azarcon for the vacant World Boxing Organisation Asia Pacific Minimumweight title on July 27, 2019. He won the fight by a first-round knockout, stopping Azarcon at the 1:12 minute mark.[8] Shigeoka made the first defense of his WBO Asia Pacific title against Rey Loreto on December 31, 2019, on the undercard of the Kazuto Ioka and Jeyvier Cintrón WBO World Super Fly title match. He won the fight by a fifth-round knockout.[9]

Shigeoka was scheduled to make his second title defense, following a 19 month absence from the sport, against the undefeated Toshiki Kawamitsu on July 14, 2021, in his first career main event. He won the fight by a second-round technical knockout.[10] Shigeoka vacated the WBO Asia Pacific minumumweight title on August 4, 2021.[11]

Shigeoka was booked to face Tatsuro Nakashima on March 27, 2022, at the City Gym in Tomigusuku, Japan,[12] for the vacant Japanese minimumweight title.[13] He won the fight by unanimous decision, with scores of 99–91, 99–91 and 98–92.[14] Shigeoka made his first title defense against the one-time Japanese mini-flyweight title challenger Naoya Haruguchi on July 7, 2022.[15] Shigeoka had a strong start to the bout, and began to take over from the third round onward, stopping Haruguchi with a flurry of punches at the 1:48 minute mark of the fourth round.[16] He vacated the Japanese title on July 29, 2022.[17]

Shigeoka was booked to challenge the reigning IBF mini flyweight titleholder Daniel Valladares. The fight was booked to take place on the undercard of the Masataka Taniguchi and Melvin Jerusalem light flyweight title bout on January 6, 2022, at the Osaka Prefectural Gymnasium in Osaka, Japan.[18] The fight was stopped at the 2:48 minute mark of the third round, after an accidental headbutt left the champion unable to continue competing. The fight was ruled a no contest. All three judges scored the fight an even 19–19 at the time of the stoppage.[19] Event organizer Kōki Kameda stated during the post-fight press conference that he would try to arrange a rematch for the April of the same year.[20]

After his no-contest bout with Valladares, Shigeoka and his team sent a request for a rematch to the IBF through the Japan Boxing Commission. As Valladares was unable to make his second title defense due to an injury, the IBF instead ordered Shigeoka to face the former IBF mini-flyweight titleholder Rene Mark Cuarto for the interim championship. The bout was booked to take place on April 16, 2023, at the Yoyogi National Gymnasium in Tokyo, Japan.[21] Shigeoka twice knocked Cuatro down, once each in the seventh and ninth round, and finished the former titlist late in the ninth round. He was briefly credited with a knockdown in the fifth round as well. He was up 78–72, 78–72 and 76–74 on the scorecards at the time of the stoppage.[22]

On June 30, 2023, it was announced that Shigeoka would rematch the IBF mini flyweight champion Daniel Valladares in a title consolidation bout on August 11, 2023. The championship bout was expected to headline the sixth edition of "3150FIGHT", which was scheduled to take place at the EDION Arena Osaka in Osaka, Japan.[23] The fight was later postponed for October 7, as Shigeoka withdrew from the contest on June 27, after suffering a leg injury in training.[24] Shigeoka won the fight by a fifth-round technical knockout.[25]