Takeru Segawa

As of 1 November 2018, he is ranked the #1 bantamweight in the world by Combat Press. As of June 2019 he is ranked as the Number 1 P4P Kickboxer in the world by Combat Press.

On March 16, 2018, RISE president Takashi Ito, former K-1 fighter Hiroya and his lawyer, accused K-1 Japan Group's exclusive contract, illegal based on the competition law. Hiroya's lawyer told the media, that the way K-1's contract work makes you not fight for a year for your contract to expire. Every fight you make with the organization, extends your contract for another year from your last fight and the only way to get out of the contract is not get paid for a year. Hiroya cites this as the reason why Segawa could not fight Nasukawa as he knows Segawa as a friend and will not back down to a fight.

On June 18, 2017, after Segawa knocked out Buvaisar Paskhaev, K-1 commentator, Masato, expressed his desire to see Segawa fight Nasukawa but the 2 other commentators ignored his comments. 2 days later, K-1's official YouTube channel uploaded the full fight video of Segawa and Paskhaev but a few hours later it was deleted and re-uploaded without Masato's comments.

On August 29, 2017 Rizin executive Nobuhiko Takada said on twitter "Two of the biggest superstars of kickboxing, Takeru vs Tenshin Nasukawa should be made right now! If this super-fight will not happen due to the (sic) cold war, it is heinous crime! Let's make this! Make miracle!" A few hours later a K-1 broadcaster trolled Takada on twitter. A few days later, Takada apologized and promised to never talk about a fighter from another organization ever again and deleted every tweet he had about Nasukawa vs Segawa.

On December 31, 2017, Nasukawa won Rizin's Kickboxing -57kg tournament. In an attempt to quash the cold war and influence K-1 and RISE to make the Segawa fight, Nasukawa made sure the show was being broadcast live so Rizin was not be able to cut any of his comments. Post-fight, in the ring, Nasukawa engaged the crowd by asking who they want him to fight next and the crowd screamed Segawa's name. In February 2018, M-1 Sports Media, which operates K-1, filed a lawsuit against Tenshin, his father Hiroyuki, RISE president Takashi Ito and Rizin president Sakakibara. According to the lawsuit, it all started three years ago when Nasukawa called out Segawa to fight. More recently during Rizin's New Year's Eve event when Nasukawa asked the audience who they want him to fight next. They claim that it's an unfair business practice to involve another fighter's name from a different organization.

In 2016, Nasukawa signed with Rizin to fight on a December event. However, K-1 suddenly ended their partnership with Rizin. K-1 have tried to avoid any mention of the fight.

Tenshin Nasukawa has been calling out Segawa since June 8, 2015. But due to contractual obligations, both fighters were not able to meet in the ring. At that time, K-1 and RISE were in a "Kickboxing Cold War" since 2010.

On August 5, 2015, Segawa told the media that he is interested in fighting Nasukawa if K-1 can organize it. K-1 Japan group producer, Mitsuru Miyata, demanded that Nasukawa sign an exclusive contract with K-1 to be able to make the fight happen. Nasukawa's trainer and RISE president, Takashi Ito, told combat sports magazine Fight & Life, that he will agree to let Nasukawa fight in a K-1 event but he's not willing to give up Nasukawa to an exclusive contract with K-1.

In 2015, K-1 officially made a partnership with the new MMA promotion, Rizin Fighting Federation. Rizin president, Nobuyuki Sakakibara, announced that Rizin is willing to make partnerships with every fighting organization so RISE began to work with Rizin as well. This deal made a Segawa–Nasukawa matchup more possible.

On November 21, 2015, Segawa made his first defense of his K-1 -55kg world title against Charles Bongiovanni, he won the fight by TKO. After the match, during the in-ring interview, Segawa announced his desire to fight in Rizin, 2 weeks after Nasukawa announced the same. When Segawa returned backstage, Nasukawa approached him and demanded the fight. The fight can happen in Rizin even with the RISE and K-1 cold war. During the press conference, Segawa mentioned that he did not recognize Nasukawa and could not understand what he was saying due to the crowd noise and thought he was just a fan. Segawa confirmed that he is willing to accept the fight if offered. After the event, Nasukawa tweeted that Segawa agreed to fight him on New Year's Eve.

On December 8, 2015, Rizin announced a fight between Segawa and Chinese fighter, Yang Ming, for their New Year's Eve event. At the press conference, Rizin president, Sakakibara, acknowledged requests to make a Segawa vs. Nasukawa fight, however, he said there wasn't enough time to promote the fight and promised to try to make it happen in 2016.