Osano was dominant in Japan in the first half of 1992, going unbeaten with wins including the Chiba International Cross Country and Shizuoka International. He also had repeat wins at the Bolder Boulder and Bay to Breakers in the United States. Osano finished third at the Kenyan Olympic trial race for the 10,000 m, but in a controversial decision the selectors decided instead to send Moses Tanui, who had failed to even complete the distance at that race. His Olympic debut thwarted, Osano did not compete again in 1992. He returned to action in May 1993 and headed to the American road circuit, taking wins at the Peachtree Road Race, Boilermaker Road Race and Bix 7 Road Race. Given his form, he was chosen for the Kenyan team at the 1993 IAAF World Half Marathon Championships. This was his only half marathon that year and he placed thirteenth in a time of 62:10 minutes, helping the team to victory with the help of fourth-placed Lameck Aguta. This proved to be his final international appearance.