WHY are the Japanese couples in Kohei Yoshiyuki’s photographs having sex outdoors? Was 1970s Tokyo so crowded,


its apartments so small, that they were forced to seek privacy in public parks at night? And what about those peeping toms?
Are the couples as oblivious as they seem to the gawkers trespassing on their nocturnal intimacy?

If the social phenomena captured in these photographs seem distinctly linked to Japanese culture, Mr. Yoshiyuki’s images of voyeurs reverberate well beyond it. Viewing his pictures means that you too are looking at activities not meant to be seen. We line up right behind the photographer, surreptitiously watching the peeping toms who are secretly watching the couples. Voyeurism is us.

The series, titled “The Park,” is on view at Yossi Milo Gallery in Chelsea, the first time the photographs have been exhibited since 1979, when they were introduced at Komai Gallery in Tokyo. For that show the pictures were blown up to life size, the gallery lights were turned off, and each visitor was given a flashlight. Mr. Yoshiyuki wanted to reconstruct the darkness of the park. “I wanted people to look at the bodies an inch at a time,” he has said.

The oversize prints were destroyed after the show, and the series was published in 1980 as a book, one now difficult to find. Last year Mr. Yoshiyuki made new editions of the prints in several sizes, which have brought renewed interest in his work. Since April images from the series have been acquired by the Museum of Modern Art in New York, the Museum of Contemporary Photography in Chicago, the Museum of Fine Arts in Houston and the San Francisco Museum of Modern Art.

Mr. Yoshiyuki was a young commercial photographer in Tokyo in the early 1970s when he and a colleague walked through Chuo Park in Shinjuku one night. He noticed a couple on the ground, and then one man creeping toward them, followed by another.

“I had my camera, but it was dark,” he told the photographer Nobuyoshi Araki in a 1979 interview for a Japanese publication. Researching the technology in the era before infrared flash units, he found that Kodak made infrared flashbulbs. Mr. Yoshiyuki returned to the park, and to two others in Tokyo, through the ’70s. He photographed heterosexual and homosexual couples engaged in sexual activity and the peeping toms who stalked them.

“Before taking those pictures, I visited the parks for about six months without shooting them,” Mr. Yoshiyuki wrote recently by e-mail, through an interpreter. “I just went there to become a friend of the voyeurs. To photograph the voyeurs, I needed to be considered one of them. I behaved like I had the same interest as the voyeurs, but I was equipped with a small camera. My intention was to capture what happened in the parks, so I was not a real ‘voyeur’ like them. But I think, in a way, the act of taking photographs itself is voyeuristic somehow. So I may be a voyeur, because I am a photographer.”

Mr. Yoshiyuki’s photographic activity was undetected because of the darkness; the flash of the infrared bulbs has been likened to the lights of a passing car.

“The couples were not aware of the voyeurs in most cases,” he wrote. “The voyeurs try to look at the couple from a distance in the beginning, then slowly approach toward the couple behind the bushes, and from the blind spots of the couple they try to come as close as possible, and finally peep from a very close distance. But sometimes there are the voyeurs who try to touch the woman, and gradually escalating — then trouble would happen.”

Mr. Yoshiyuki’s pictures do not incite desire so much as document the act of lusting. The peeping toms are caught in the process of gawking, focused on their visual prey. Alexandra Munroe, senior curator of Asian art at the Guggenheim Museum, suggested in a telephone interview that this phenomenon was not uncommon in Japan. She cited the voyeurism depicted in Ukiyo-e woodblock erotic prints from 18th- and 19th-century Japan, in which a viewer watches a couple engage in sexual activity. “It’s a consistent erotic motif in Japanese sexual imagery and in Japanese films like ‘In the Realm of the Senses,’ ” she said.

Karen Irvine, curator of the Museum of Contemporary Photography in Chicago, said Mr. Yoshiyuki’s work is important because “it addresses photography’s unique capacity for observation and implication.” She locates his work in the tradition of artists who modified their cameras with decoy lenses and right-angle viewfinders to gain access to private moments. Weegee, for example, rigged his camera to capture couples kissing in darkened New York movie theaters. Walker Evans covertly photographed fellow passengers on New York subways.

“Like the work of these artists,” Ms. Irvine said, “Yoshiyuki’s photographs explore the boundaries of privacy, an increasingly rare commodity. Ironically, we may reluctantly accommodate ourselves to being watched at the A.T.M., the airport, in stores, but our appetite for observing people in extremely personal circumstances doesn’t seem to wane.”