Born in Sagamihara, she attended Kanagawa Prefectural Asamizodai High School and competed in the 1500 metres as a teenager. A small and light runner – 1.55 m tall (5 ft 1 in) and 39 kg in weight (86 lbs) – she made her first appearance at the Japan Championships in Athletics in 2005, finishing fourth in the 1500 m final. She broke through at the senior level the following year, winning the Japanese title, running at the World Cross Country Short Race and placing seventh at the 2006 Asian Games.