Kubo is a 24 year old southpaw from Hyogo and although he's looked very good so far he's actually unranked by the Japanese Boxing Commission. He is however ranked #7 at Bantamweight by the OPBF, a ranking that he earned courtesy of his decision win over the experienced Filipino Monico Laurente last November. Aside for Laurente it's fair to say Kubo hasn't scored another notable win, yet.
The Japanese fighter will be hoping to change that on December 19th when he takes a huge step up in class to fight against Mexican Luis May (15-7-1, 7), a man currently ranked #11 by the WBC in their world rankings. May is not only more experienced than Kubo but he has also mixed with some notable fighters including Jose Salgado, who defeated him with a 10 round decision, Juan Francisco Estrada, who took an 8 round decision over him, and Cesar Seda, who was dropped en route to an 8 round win over May. Despite those losses May has also scored a recent notable win over Daniel Noriega and is currently unbeaten in 5 bouts.
Whilst Kubo is tipped as a future champion by those in the know this is still an extremely big step up in class. A win could see him rewarded with a WBC world ranking and, after 6 fights, he would suddenly become a fighter that hardcore fans would likely take an interest in. A loss for Kubo obviously wouldn't be great but at this stage in his career it would be little more than a temporary setback for a man who seems to be full of confidence.