Today it was revealed that Koseki had vacated that title, and the WBC Atomweight title, and was retiring from active boxing at the age of 34, gollowing an exceptional career.
Although relatively unknown outside of the hardcore of the hardcore Koseki was the torchbearer for the Atomweight division. She won the WBC title way back in August 2008 and went on to make an incredible 17 defenses, unifying the WBA title along the way with a win over Ayaka Miyao in 2015.
Although Koseki suffered a couple of early career defeats, losing 2 of her first 5 bouts, she went on to have an excellent career and score notable wins over Kuroki, Miyao, Nao Ikeyama and Saemi Hanagata and claim 3 world titles during her 27 fight career. She achieved the goals of becoming a unified champion and a multi-weight champion and clearly retires on her terms.
Today she stated that the bout with Kuroki was to be her last, that she had achieved her goals, and that she was now planning to begin vocational education in April to become a Physiotherapist.
(Image courtesy of boxmob.jp)