The humble Naito will be the popular favorite when he steps into the ring at Saitama Super Arena against the brash 23-year-old Kameda, who has been widely criticized here for his flamboyance, immaturity, and lack of respect both inside and outside the ring.
Ever since a win over Koki's brother Daiki two years ago, Naito has become a celebrity in Japan, regularly appearing on TV shows where his soft-spoken demeanor and humble personality has won over fans.
The 35-year-old Naito took up boxing to defend himself in school where he was the victim of bullying and often speaks out in support of those subjected to similar abuse.
Naito claimed the tile by defeating Thailand's Pongsaklek Wonjongkam in 2007, five years after his first world title shot against the same opponent. He had retained it through five subsequent bouts.
"I've put in a lot of training," Naito said ahead of Sunday's fight. "At 35, you do worry about losing a bit of stamina but I'm in great shape and am psychologically sharper than he is."
Kameda, along with his brother Daiki, quickly established a reputation for cockiness. Forgoing the niceities of the Japanese language, Kameda taunts his opponents with insults and bold predictions. True to form, he was confident about his chances against Naito in a pre-bout interview.
"I hope to knock him out," Kameda said. "It's been a long time since I felt this confident and I can't wait for the fight to begin."
The undefeated Kameda is making his first attempt at a major world title.
Despite getting knocked down in the first round and being dominated in the final two rounds, Kameda came away with a split decision against Venezuela's Juan Jose Landaeta in August of 2006 to claim the WBA World light flyweight belt.
The Japanese TV station that broadcast the fight received over 50,000 calls complaining about the outcome.
The bad blood between Naito and Kameda goes back several years.
Naito defeated Koki's younger brother Daiki by unanimous decision for the first defense of his WBC title in Oct. 2007. Naito outclassed the younger Kameda despite being fouled throughout the fight.
The fight deteriorated into a free for all with Daiki Kameda at one point lifting Naito up by his waist and slamming him to the mat.
Fans were shocked by Kameda's behavior and outraged when it was revealed that Koki advised his brother to elbow Naito's eye.
Before the bout, Daiki described Naito as a "cockroach" and stated that he would commit hara-kiri (ritual suicide) if he were to lose.
The Kamedas made a tearful apology after the fight but Daiki's boxer's license was suspended by the Japan Boxing Commission for one year for professional misconduct.
