The smallest world champions are in what is called the Minimum division at 105 pounds. Two are from Thailand and two are from Japan so unification bouts should be rather easy one would think.
The top champion is the WBC Champion Chayaphon Moonsri, 49-0 (17), from Bangkok, Thailand. He is scheduled to fight on May 2nd at the Nakhon Ratchasima Provincial Ground in Thailand. His opponent is the No. 1 contender southpaw Leroy “El Sensacional” Estrada, 16-2 (6), of La Chorrera, Panama.
If Moonsri who will be making his ninth defense since winning the title in November of 2014 wins he will surpass the record of former world heavyweight champion Rocky Marciano and equal former champion Floyd “Money” Mayweather at 50-0 who has yet to announce his retirement.
Moonsri is the sixth boxer to equal or pass Marciano’s 49-0 record which he held for over sixty years. Moonsri is 5:02 and the oldest of the four champions at age 32. His last defense was on November 25th. All his fights have been in Thailand.
The WBA World Champion is Thammanoon Niyomtrong, 17-0 (7), of Surin, Thailand. He won his title in June of 2016 and has defended his title four times. He is the shortest at 5:01 and is at age 27. His last defense was March 6th. He has had all his fights in Thailand.
The IBF World Champion is Hiroto Kyoguchi, 9-0 (7), of Tokyo, Japan. He won his title in July of 2017 and made his lone defense in December. He is 5:03 1/2 with all but one fight in Japan and that was in Thailand.
The WBO World Champion is Ryuya Yamanaka, 16-2 (5), of Kobe, Hyog, Japan. He won his title in August of 2018 and made his lone defense on March 18th. He is age 22 and all his fights have been in Japan.
If Moonsri and Thammanoon Niyomtrong both of Thailand would meet and Kyoguchi and Yamanaka both of Japan meet there would be a good chance of a unified World Minimum Champion. The next weight class up is at 108 pounds in the Light Flyweight division with three world champions from Japan and one from Puerto Rico.
Thailand’s top Flyweight Champion was Pone Kingpetch, 28-7 (9). Japan’s Fighting Harada, 55-7 (22) was their top Flyweight and Bantamweight Champion. They split in their two meetings.