岡崎市
Kimura was born in Okazaki, Aichi Prefecture. From an early age he was very interested in botany, though he also excelled at mathematics (teaching himself geometry and other maths during a lengthy convalescence due to food poisoning). After entering a selective high school in Nagoya, Kimura focused on plant morphology and cytology; he worked in the laboratory of M. Kumazawa studying the chromosome structure of lilies. With Kumazawa, he also discovered how to connect his interests in botany and mathematics: biometry.