Career
Kozo began his career with Yokohama Flugels and played later for the Waseda University. In 2002 he left Waseda University. He was now scouted by JEF United Ichihara Chiba.
After seven years for JEF United Ichihara Chiba he was loaned out to Sanfrecce Hiroshima in January 2008.
On 20 July 2009, the 2. Bundesliga club Fortuna Düsseldorf signed the Japanese Defender until the end of the year.