小沢治三郎
Operation PX, also known as "Cherry Blossoms at Night", was proposed in December 1944 by the Japanese Naval General Staff, led by Vice-Admiral Jisaburō Ozawa. The name for the operation came from the Japanese use of the code name PX for Pestis bacillus-infected fleas. In planning the operation, the navy partnered with Lieutenant-General Shirō Ishii of Unit 731, who had extensive experience on weaponizing pathogenic bacteria and human vulnerability to biological and chemical warfare.