1973-01-02 Masao Ohba w co 12 (15) Chartchai Chionoi, Nihon University Auditorium, Tokyo, Japan - WBA
1973-01-02 Masao Ohba w co 12 (15) Chartchai Chionoi, Nihon University Auditorium, Tokyo, Japan - WBA. Referee: Yusaku Yoshida. Having survived a first-round knockdown, and picking up a badly damaged leg muscle into the bargain, Ohba (111½) had got going by round seven, it being just one-way traffic from then on. Finally, in the 12th, when the champion put his punches together Chionoi (109¼) was in trouble, being floored three times before the referee counted him out as the bell rang to end the round.
After Ohba died in a road accident on 24 January 1973, Chionoi and Fritz Chervet, the European champion, were selected to contest the vacant title. In 58 contests, Chervet had won 49, drawn two and lost seven, and numbered John McCluskey (twice), Kamara Diop and Fernando Atzori among his victims.