Manabu Koga (5 April 1935 – 18 May 1974) was a Japanese freestyle swimmer who competed in the 1956 Summer Olympics. References 1935 births 1974 deaths Japanese male freestyle swimmers Olympic swimmers of Japan Swimmers at the 1956 Summer Olympics World record setters in swimming Asian Games medalists in swimming Swimmers at the 1958 Asian Games Asian Games gold medalists for Japan Medalists at the 1958 Asian Games 20th-century Japanese people