In elementary school Kai trained karate and sumo, as well as spending three years training volleyball.[5]
Kai and his brother, Mikuru, spent much of their childhood getting involved in numerous street fights. The brothers would often fight each other as well, to which Kai attributes his toughness as a professional mixed martial artist. As they were entering their adolescent years, at the suggestion of a therapist, their mother enrolled them into boxing classes.[6]
Whilst a third year student at Aichi Prefectural Toyohashi Technical High School, his brother took him to the Zen Dokai Toyohashi Dojo, which was Kai’s first introduction to mixed martial arts.[7] It was at the insistence and encouragement of his brother, Mikuru, that he took his interest in fighting.[8]
Mixed martial arts career
Early career
Asakura began his professional career under the banner of DEEP, when he faced a fellow debutante Tomoya Suzuki. Asakura won the bout via a first round TKO.[9]
He would then fight with Fighting Network Rings new brand of MMA events named Outsider, after a three-year hiatus. He faced Satoshi Date, whom he defeated in the second round by TKO.[10] Two months later he faced Keigo Takayama winning the fight after just 40 seconds via technical knockout.[11] Two months later he fought a debuting Jung Bin Choi, earning his first career submission, forcing Choi to tap to a D'Arce choke in the first round.[12] Asakura's next opponent was Jong Hyun Kwak. Asakura again ended the fight in the first round, winning through a TKO.[13]
Fighting with Road Fighting Championship, Asakura fought Liu Xiaoyang, who he beat by an RNC in the first round.[14] Fighting for the Fighting Network Rings 60 kg title, Asakura faced Yoichi Oi. He won the title fight in the first round, defeating Oi at the very end of the first round by technical knockout.[15] Asakura's next opponent was Alateng Heili, who was riding a six-fight winning streak. Asakura won the fight after 29 seconds, hitting Heili with a short left hook, followed by a knee strike.[16] Asakura suffered his first career loss to Je Hoon Moon during Road FC 39, losing via technical knockout.[17]
Rizin Fighting Federation
Asakura made his Rizin debut on 29th December 2017, during RIZIN Fighting World Grand Prix 2017. Asakura was scheduled to fight the ZST Flyweight Champion Seiichiro Ito. Ito suffered a nasal fracture before the bout, and was replaced by Kizaemon Saiga.[18] Kai won the fight in the second round after knocking Saiga out with a grounded knee.[19]
During Rizin 10, Asakura faced bantamweights, Manel Kape. After suffering an early knockdown, he went on win a split decision, which would be named as a Fight of the Month nominee for May of 2018 by MMA Junkie.[20]
Asakura was next scheduled to fight Thanongsaklek Tiger Muay Thai at Rizin 11.[21] The fight was subsequently rescheduled for Rizin 13, after Asakura injured his right knee. At Rizin 13 and he won a unanimous decision.[22]
During RIZIN Heisei's Last Yarennoka!, Asakura rematched with Je Hoon Moon.[23] Asakura won via unanimous decision.[24]
Asakura's face Ulka Sasaki. at Rizin 15. However, Sasaki had to pull out due to injury and was replaced by Justin Scoggins. Scoggins would then pull out of the bout after he suffered a meniscus and ligament tear in his knee.[25]
His next fight was scheduled for Rizin 18 as a non-title bout against the Rizin bantamweight champion Kyoji Horiguchi. Asakura would feint Horiguchi backward and landed a big right hand as Horiguchi was blitzing in. Following up with knees and punches, Asakura won the fight via knockout.[26]
Two months later he faced Ulka Sasaki at Rizin 19.[27] Asakura dominated Sasaki, jitting the veteran with a right hand, and following up with grounded knees and soccer kicks and won the fight via technical knockout, as Sasaki was unable to continue due to a broken jaw.[28]
Title reign
This six-fight winning streak gave Asakura a chance to fight for the Rizin bantamweight strap, in a rematch against Kyoji Horiguchi during Rizin 20.[29] Horiguchi pulled out of the bout due to a knee injury and vacated the belt. Asakura faced Manel Kape in a rematch for the vacant Rizin Bantamweight Championship. Kape knocked Kai down twice in the beginning of the second round which forced the referee to stop the fight.[30]
Asakura was scheduled to make his first title defense in a rematch with the former Rizin Bantamweight champion Kyoji Horiguchi during Rizin 26 – Saitama.[35] He lost the fight by a first-round TKO.[36]
Rizin Bantamweight Grand Prix 2021
Asakura faced Shooto Watanabe in the opening round of the Bantamweight Grand Prix at Rizin 28 on June 13, 2021. [37] He won the fight by a first-round technical knockout.[38]
Asakura faced Alan Yamaniha in the quarterfinals on September 19, 2021 at Rizin 30.[39] He won the fight by unanimous decision.[40]
In the semi-finals, Asakura faced Kenta Takizawa on December 31, 2021 at Rizin 33.[41] He won the fight by unanimous decision, and advanced to the tournament finals, where he faced Hiromasa Ougikubo.[42] He lost the bout via unanimous decision, becoming the runner up in the Grand Prix.[43]
Continued bantamweight career
Asakura was expected to face the undefeated Ji Yong Yang at Rizin 36 on July 2, 2022.[44] Asakura withdrew from the fight on June 30, as he had re-injured his right hand.[45]
Asakura faced Yuki Motoya at Rizin 42 on May 6, 2023.[46] He won the fight by a second-round flying knee knockout.[47]
Asakura faced Juan Archuleta for the Rizin Bantamweight Championship on December 31, 2023, at Rizin 45.[50] At the weigh-ins, Archuleta weighed in at 140.65 pounds, 5.65 pounds over the limit. As a result, Archuleta was stripped of the title and only Asakura was eligible to win it.[51] Asakura won the bout via technical knockout in the second round.[52]
Won the vacant Rizin Bantamweight Championship. Archuleta missed weight (140.65 lb) and was stripped of the title. Only Asakura was eligible to win title. Later vacated it on 9 June 2024.
