Kazuto Ioka continued a time-honored tradition in style, forever cementing his place as a modern-day great while denying history at his expense in the process.

The four-division and reigning WBO junior bantamweight titlist denied the same status sought by previously unbeaten Kosei Tanaka, scoring two knockdowns en route to an 8th round stoppage win Thursday evening at Ota-City General Gymnasium in Tokyo.

Ioka scored knockdowns in rounds five and six, before stopping Tanaka on his feet (barely) midway through round eight of their TBS-Japan televised headliner.

Ioka sought to make his presence felt right from the opening bell, coming out swinging with a left hook. Tanaka immediately adjusted, the former 105-, 108- and 112-pound titlist taking a slight step back and digging in with his jab. The unbeaten challenger connected with a straight right hand, followed by a left uppercut. The Osaka-bred, Tokyo-based Ioka ended the frame in textbook fashion, landing a left hook to the body as well as one up top.

Tanaka took the lead in round two, landing in combination and his hand speed proving to be an issue. Ioka turned the tide late in the round, power punching his way to the bell before relying more on his superior defensive skills in a round three where Nagoya's Tanaka considerably outworked his elder countryman.

Both fighters showed battles scars by the end of round four. Ioka was forced to contend with a mouse around his left eye, while Tanaka was bleeding from his nose though neither seemed bothered by the wounds. 

Tanaka would become very bothered by the end of round five. Both fighters had their say in a high contact and competitive frame but it was Ioka who would have the final word. A left hook by the 31-year old sent Tanaka tumbling to the canvas for the bout's first knockdown. 

"After he went down, I knew he had lost his temper," Ioka said after the fight, as translated to BoxingScene.com by manager Taku Nagashima. "I told myself that this is the time to gather my composure and really show him that I am a superior boxer."

Ioka would grow braver in round six, the risk proving well worth the reward. Tanaka showed tenacious recuperative skills, punching his way back into the lead before getting clipped again. A right hand sent the former three-division titlist to the canvas, rising quickly but suddenly in a deep hole through six rounds. 

The second half of the fight opened with Tanaka switching between conventional and southpaw, while also looking to work the body. Ioka wisely kept his distance, wise enough to not fall in love with his own power and pursue a knockout that wasn't there for the taking. 

That opportunity would come mere moments later.

Ioka closed the show in style in round eight. Tanaka came out in a conventional stance, firing his jab and looking to bully his elder foe. Ioka played just enough defense to minimize the damage before moving in to close the show. A left hook by Ioka rocked Tanaka, with referee Michiaki Someya immediately jumping in to rescue the battered fighter.

The official time was 1:35 of round eight. Ioka was ahead 69-62, 68-63 and 68-63 at the time of the stoppage.

"It was a fight that showed Ioka is highly underrated," Nagashima told BoxingScene.com. "When I saw the odds as him being an underdog, it was unbelievable to me.  This was not close to being a fight of the year, but it was a clinic on boxing technique and intellect.  

"This is a big step towards unifying the belts in the [115-pound] division."

Tanaka suffers his first career defeat, falling to 15-1 (9KOs) as he was denied a fourth division title, at least on his first try. A win by the all-action hero would have shattered the all-time mark for the fastest to title status at four different weights.

For now, the mark remains with Oscar de la Hoya who accomplished the feat in his 24th fight—a 12-round nod over Pernell Whitaker to claim the lineal welterweight championship en route to winning titles in six weight divisions.

Instead, Tanaka will have to settle for his shared history with Vasiliy Lomachenko as the fastest to three divisional titles by any male boxer. Both did so by their 12th pro fight, Tanaka accomplishing the feat in his Sept. 2018 flyweight title winning effort over Sho Kimura to match the record set by Lomachenko just four months prior. 

It stands to reason that his day could eventually come at some point within his next eight fights.

"I want to thank Tanaka who is a young boxer that will eventually be one of the boxers to carry the torch for Japan," acknowledged Ioka, who improves to 26-2 (14KOs) while retaining sole possession of a significant piece of boxing history.

Thursday's win marks the second defense of the 115-pound title claimed in a 10th round stoppage of Philippines' Aston Palicte last June in Chiba, Japan. With that win, Ioka became the first-ever male boxer from Japan to win titles in four weight divisions, a run which began with a 5th round knockout of then-unbeaten strawweight titlist Oleydong Sithsamerchai way back in Feb. 2011.

From there came the start of a tradition of world championship boxing on New Year's Eve. Ioka headlined his first year-end show on Dec. 31, 2011, knocking out unbeaten Thai challenger Yodgoen Tor Chalermchai in just 98 seconds. 

The win marked the first of nine career New Year's Eve main events, with Ioka now 8-1 on the festive occasion.

Six months later came the final fight of his strawweight title reign, also providing a watershed moment in Japanese boxing history. A spirited 12-round unanimous decision win over Akira Yaegashi in June 2012 marked the first-ever—and to date, only—unification bout between reigning titlists from Japan.

The second title reign for Ioka would begin later that year, scoring a 6th round stoppage of Jose Alfredo Rodriguez to win a vacant 108-pound belt on New Year's Eve 2012. Three title defenses would follow, the last of which came exactly one year later in a 12-round decision over Felix Alvarado who presently serves as a junior flyweight titlist.

It would take two tries and 16 months for Ioka to win a flyweight title. The first defeat of his career came in May 2014, dropping a 12-round decision to Amnat Ruenroeng in his first attempt at a flyweight belt. Success would come 50 weeks later, edging Juan Carlos Reveco over 12 rounds in April 2015 before stopping the Argentinean in the 11th round of their rematch later that year on New Year's Eve 2015.

Ioka's lone New Year's Eve loss came in Dec. 2018, two fights into his comeback after abruptly retiring in 2017—the only year among the past ten where he didn't fight on New Year's Eve. It was also the only time he spent the holiday in another country, as he dropped a competitive split decision to Donnie Nietes in their vacant 115-pound title fight in Macao. 

History was denied for Ioka in looking to become Japan's first-ever male boxer to win belts in four divisions, though doing so six months later in his aforementioned win over Palicte. The first title defense came last New Year's Eve, outpointing Jeyvier Cintron—an unbeaten contender and two-time Olympian for his native Puerto Rico. 

The same show saw Tanaka make the final defense of his flyweight title, stopping Wulan Tuolehazi inside of three rounds in the evening's chief support. From there, Tanaka announced his intention to campaign at junior bantamweight where he immediately pursued a mandatory title fight with Ioka.

A deal was reached only for their historic clash to suffer a months-long delay due to the ongoing coronavirus pandemic. It proved well worth the wait at least for Ioka, who now gets to play with house money for the rest of a career unquestionably destined for the International Hall of Fame whenever he decides to hang up the gloves.

That day is not coming anytime soon, however. At least, it won't come before he has a chance to reap the benefits of a junior bantamweight division which has never been more lucrative.

Waiting in the wings are potential challenges with lineal 115-pound champion Juan Francisco Estrada (41-3, 28KOs), four-division and reigning WBA junior bantamweight titlist Roman 'Chocolatito' Gonzalez (50-2, 41KOs) and former lineal champ Srisaket Sor Rungvisai (49-5, 42KOs).

Estrada and Gonzalez are due to collide on March 13, more than eight years after their memorable 12-round war in Nov. 2012 at junior flyweight. Sor Rungvisai is the WBC mandatory challenger due to face the winner.

Also in discussion is a third fight between reigning secondary WBA titlist Joshua Franco and former claimant Andrew Moloney. Rounding out the group is long-reigning IBF beltholder Jerwin Ancajas, who remains in desperate need of a relevant challenge.

"In our 115 division, there are great champions," acknowledges Ioka. "I would like to take the show internationally to fight the best."

Jake Donovan is a senior writer for BoxingScene.com. Twitter: @JakeNDaBox