Kaji can play on either side of defence, while his ability to adapt has also seen him utilised as a midfielder at times during his career. He made his international debut against Tunisia in October 2003 and is nearing the 50-cap mark. The 26-year-old started his career with Cerezo Osaka, but now plays his club football for FC Tokyo, where he has been a regular starter for four years. He was a prominent member of the Confederations Cup squad last year and is a likely starter in Germany.