Check out my rankings within each division by clicking on the links below. If there is a lineal champion in the weight class he is ranked No. 1.
Who is the best fighter regardless of weight class? See ESPN's pound-for-pound rankings.
For a list of the current champions in all weight classes, click here.
Note: Results through Dec. 18. In an effort to provide the most up-to-date rankings, ESPN.com's division-by-division boxing rankings will be updated every Tuesday.
More Divisional Rankings
FLYWEIGHT DIVISION (UP TO 112 POUNDS)
1. Kazuto Ioka (22-1)
Japan's Ioka, who has won world titles at strawweight, junior flyweight and flyweight, has made five successful flyweight defenses, including a unanimous decision win against Thailand's Noknoi Sitthiprasert on April 23 in Ioka's hometown of Osaka. Sitthiprasert, who dropped to 62-5, was facing his first quality opponent and paid the price: Ioka pounded him to the body throughout the fight as Sitthiprasert suffered his first loss since 2005. Ioka has been ordered to make his mandatory defense against Ukraine native Artem Dalakian (15-0), but instead elected to vacate his belt.
2. Donnie Nietes (40-1-4)
After four strawweight title defenses, the Philippines' Nietes vacated his belt and moved up to junior flyweight, where he won another title and made nine defenses. Nietes vacated his world title and moved up to flyweight in September 2016, cruising to a shutout decision against former junior flyweight titleholder Edgar Sosa. The win set up Nietes to face Thailand's Komgrich Nantapech for a vacant flyweight title on April 29, and he got the job done, winning a unanimous decision to become a three-division titlist. He is due to make his mandatory defense against Argentina's tough Juan Carlos Reveco, likely in February with sites in the United States, China and the Middle East being considered.
Next: TBA vs. Reveco
3. Daigo Higa (14-0)
Japan's Higa looked fantastic on May 20 as he scored five knockdowns against Mexico's Juan Hernandez in a sixth-round knockout victory to win a vacant title that had been stripped from Hernandez the previous day for failing to make weight. Higa's first defense came on Oct. 22 in Tokyo and he was also impressive taking apart France's Thomas Masson, the European champion, whom he busted up and stopped in the seventh round. Defense No. 2, which will also take place in Japan, will come against Mexico's Moises Fuentes (25-4-1), a former strawweight world titleholder.
Next: Feb. 4 vs. Fuentes
4. Juan Carlos Reveco (39-3)
Argentina's Reveco, a former junior flyweight and flyweight world titleholder, squared off with former flyweight world title challenger Komgrich Nantapech of Thailand on Sept. 8 in a title eliminator for the right to become Donnie Nietes' mandatory challenger. Reveco cruised to a unanimous decision on scores of 120-108, 118-110 and 117-111. He is supposed to get his shot at Nietes (40-1-4) next with Jan. 16 the target date.
Next: TBA vs. Nietes
5. Sho Kimura (15-1-2)
Japan's Kimura was the hand-picked opponent to challenge China's Zou Shiming for his word title on July 28 in Shanghai. Kimura, the big underdog, trailed on two scorecards going into the 11th round when he pulled the stunner and knocked Zou out for the upset. Kimura will make his first defense against former flyweight titlist Toshiyuki Igarashi (23-2-3) on a traditional New Year's Eve card in Japan.
Next: Dec. 31 vs. Igarashi
Other contenders: Moruti Mthalane, McWilliams Arroyo, Andrew Selby, Vincent Legrand, Brian Viloria.