Born in Takasaki, Gunma, she attended Sendai Ikue High School – an institution renowned for its athletic programme. Kinukawa made her first impact on the national junior circuit in 2006, as she won the junior race at the Fukuoka International Cross Country and was runner-up at the Chiba Cross Country two weeks later. This gained her a debut international selection at the 2006 IAAF World Cross Country Championships (also held in Fukuoka), where the sixteen-year-old came in fourteenth place and helped the Japanese girls to a team bronze medal. Turning to the track later that April, she ran a national junior record in the 10,000 metres at the Hyogo Relay Carnival, placing second behind Lucy Wangui with a mark of 31:35.27 minutes – raising her to eleventh on the all-time junior rankings.