Nawa was born in the Motosu District of Gifu Prefecture (present day city of Mizuho) and had a strong affinity to bugs even in his youth. In 1878, he entered into the Gifu Agricultural Learning Center (which later became the Gifu Prefectural Agricultural School and is now the Gifu Prefectural Agricultural High School) and stayed on at the school as an assistant after he graduated in 1882.
Nawa was born in the Motosu District of Gifu Prefecture (present day city of Mizuho) and showed a predilection for entomology even at a young age. He then attended the Gifu Agricultural Learning Center, which eventually became the Gifu Prefectural Agricultural School, and continued to work there as an assistant after graduating in 1882.