Kohei Yoshiyuki (吉行耕平, Yoshiyuki Kōhei, born 1946) is a Japanese photographer who attracted much attention in 1979 with his exhibition "Kōen" (公園, Park) at the Komai Gallery, Tokyo. The black-and-white photographs were presented in a book published in 1980 that is "nominally a soft-core voyeur's manual", with photographs of people in sexual activities in Shinjuku and Yoyogi parks (both in Tokyo), mostly with unknown spectators around them. The photographs were taken with a 35 millimetre camera and infrared flashbulbs. Gerry Badger and others have commented on how the photographs raise questions about the boundaries between spectator, voyeur and participant.