Kaichi Watanabe (渡邊 嘉一, Watanabe Kaichi, 22 March 1858 – 4 December 1932) was a Japanese engineer who studied and worked in Scotland, United Kingdom during the 1880s.

Watanabe studied under Henry Dyer, the Scottish engineer associated with technical education in Japan.

After obtaining a degree from the Faculty of Technology of the University of Tokyo, he studied at the University of Glasgow from 1885 and graduated with a Civil Engineering and Bachelor of Science degree,[1] and worked as a construction foreman on the Forth Bridge, which crossed the Firth of Forth in eastern Scotland in 1890.

[2] Watanabe's image became well known in the 1887 photograph illustrating the cantilever principle, in which he poses with Fowler and Baker, suspended between the engineers who form a cantilever structure with their arms.

[3] Watanabe returned to Japan in 1888, where he became the chief engineer of the Nippon Doboku Company.