In 1997, Ogawa was recruited by
Antonio Inoki, chairman of
New Japan Pro-Wrestling, for his UFO (Universal Fighting-Arts Organization) project. He was put to train under
Satoru Sayama, legendary professional wrestler and
mixed martial arts pioneer.
New Japan Pro-Wrestling (1997–2001) Ogawa made his debut in NJPW on April 12, 1997 at the
Tokyo Dome, replacing the stipulated
Ken Shamrock as the opponent for
Shinya Hashimoto, then IWGP Heavyweight Championship titleholder. In a shocking upset, Ogawa defeated Hashimoto by choke, which put him in the spotlight and gained him a title shot at May 3. This time Ogawa was defeated by kick to the head, with Shinya retaining his title. This marked the beginning of their feud, which would extend for years. Through 1997 and 1998, Ogawa wrestled for NJPW as part of "Different Style Fights", meeting wrestlers with legit backgrounds like Ogawa and Hashimoto themselves. He defeated
shoot-style wrestler
Kazuo Yamazaki,
arm wrestler Scott Norton,
Ultimate Fighting Championship exponents
Brian Johnston and
Don Frye, and Dutch martial artist Erwin Vreeker. His only loss came from
The Great Muta, via Muta's signature Asian mist dirty trick. In March 1998, Ogawa took part in the Inoki Final Tournament, but he was eliminated by Frye at the finals after beating Johnston and
Dave Beneteau. In order to bounce back from the defeat, he started a special training, and ditched his trusted
judogi for black tights, boots and
fingerless gloves. On January 4, 1999, Ogawa was involved with one of the most controversial moments in NJPW history. During his anticipated rubber match with Shinya Hashimoto, Ogawa broke
kayfabe and
shot on Hashimoto, attacking him for real and leaving him downed and bloodied with kicks and stomps. The NJPW and UFO crews flooded the ring and a legitimate fracas erupted, with Ogawa's
cornerman Kazunari Murakami having to be hospitalized by a beatdown by
Takashi Iizuka and Naoya himself being slapped by NJPW executive
Riki Choshu. During all the brawl, Ogawa taunted the crowd and the wrestlers, having to be accompanied out of the arena by his bodyguard
Gerard Gordeau. Many years later, in August 2021, Ogawa confessed he had been pressed by
Antonio Inoki into shooting on Hashimoto in order to hijack the match and increase his popularity. In May, Ogawa traveled to United States and defeated
Gary Steele to win the
NWA World Heavyweight Championship. Hashimoto followed him to the country and attacked him (kayfabe this time) in a press conference, challenging him to a title match in Japan with
Tatsumi Fujinami as special referee. Naoya toured through United States, retaining the title before
Dan Severn,
Doug Gilbert and Biggie Biggs, trading it with Steele in a three-way match that also involved Brian Anthony on September 25, 1999, and finally coming back to Japan to meet Hashimoto. They faced on October 10 at the Tokyo Dome, with Ogawa winning the bout. On January 4, 2000, one year after their incident, Ogawa and Murakami faced off against Hashimoto and Takashi Iizuka in a special match. Unfortunately, it became a real fight again when Murakami knocked Iizuka out legitimately with a
stiff head kick, causing the teams to brawl in the ring again. Under Antonio Inoki's eye, the match was restarted, with Ogawa's team losing when Iizuka choked out Murakami. After a tense alliance between them formed for the Rikidozan Memorial, Hashimoto challenged Ogawa to a last match, in which Hashimoto would retire from professional wrestling if he lost. Ogawa and Hashimoto fought the last time of their careers on April 7 at the Tokyo Dome, where Naoya defeated Hashimoto by KO after several iterations of his
Space Tornado Ogawa technique. His opponent carried out and performed a retirement ceremony, while Inoki and other tried to convince him not to do it; even Ogawa declared in a segment that he repented having finished off the career of his rival. Ogawa vacated the NWA title on July 2, 2000 in order to focus on training for his fight against
Rickson Gracie, which never took place.
Pro Wrestling Zero-One (2001–2004) In 2001, after Shinya Hashimoto founded
Pro Wrestling Zero-One, Ogawa left NJPW and moved in, forming a tag team with his former rival which was called "OH Gun". Their beginning together was harsh, but they eventually got along and won the
NWA Intercontinental Tag Team Championship from the UPW team of
Jon Heidenreich and
Nathan Jones. Ogawa and Hashimoto, along with the rest of native wrestlers of Zero-One, entered in a feud with the foreign wrestlers, led by
Tom Howard and
Steve Corino.
Hustle (2004–2007) In 2004, Ogawa took part in the foundation of the
sports entertainment promotion
Hustle, a combined effort between Zero-One and
mixed martial arts league
Pride Fighting Championships. Ogawa opened the storyline of Hustle during a staged press conference with Pride chairman
Nobuyuki Sakakibara. During the interview, Sakakibara criticized professional wrestling and declared it inferior to MMA, which turned Ogawa furious. With
Nobuhiko Takada acting on behalf of Sakakibara and Shinya Hashimoto backing Ogawa, it was decided they would prove their postures in an event where MMA fighters would face professional wrestling representatives. Ogawa himself would be slated to wrestle
Bill Goldberg, who had been introduced by Takada as his champion. However, the night of the event turned sour as, although Ogawa managed to overpower Goldberg, Takada ordered
Giant Silva to attack Ogawa and distract him to be finished off by Goldberg. At the second Hustle event, when Takada proclaimed himself Generalissimo Takada, leader of the villainous Monster Army, and declared his goal was to destroy professional wrestling, Ogawa and Hashimoto founded Hustle Army, a union of professional wrestlers bent on protecting their guild. Ogawa became the leader of the army, being nicknamed "Captain Hustle" and debuting a characteristic
hip thrust gesture to chant Hustle's name. Although his first match was a loss, being pinned by
Matt Ghaffari with the help of several Monster Army members, he bounced back by summoning several high level wrestlers, among them
Riki Choshu and
Toshiaki Kawada, to help him and Hashimoto. In September, after Ogawa lost to
Fedor Emelianenko in 54 second at a Pride event, Takada started a mocking campaign against him and banned him from competing in Hustle for 54 days. In order to overcome this ban, Ogawa disguised himself as "Captain O", a masked
gimmick based on
Hulk Hogan's Mr. America persona, whom Ogawa claimed was the true Hogan in disguise. Deducting Captain O was really Ogawa, Takada's second-in-command
Commander An Jo sent several Monster Army wrestlers to capture and tie him up, but O escaped by shedding this gimmick and adopting yet another, "Judo O", where he would wear a blue
judogi along with his mask. Judo O teamed up with
Hustle Rikishi to defeat Takada's slave
Hakushi and a one night mercenary named
Russian 54. After Ogawa returned to the ring, Hustle co-produced a show along with
Michinoku Pro Wrestling, whose star The Great Sasuke was inducted in the Hustle Army. In 2007, Ogawa disappeared from the Hustle Army and sided shockingly with Takada. Ogawa changed his persona to an arrogant
socialite gimmick and called himself "Monster Celebrity", wearing sunglasses and ornated coats. Takada explained Ogawa had been brainwashed by him to turn him in one of his henchmen, and he proved Ogawa's newfound loyalty by sending him to attack Hustle Army member Banzai Chie. This storyline was written in order to explain Ogawa's departure from Hustle, as he had signed up with
Antonio Inoki's new promotion,
Inoki Genome Federation.
Inoki Genome Federation (2007–2015) Ogawa worked for
Inoki Genome Federation until his retirement in 2015. ==Mixed martial arts career==