TOKYO -- Some tasks simply cannot be automated -- even in Japan.
In a bonded warehouse in the port of Yokohama's customs area, dozens of housewives sit at rows of desks, armed with coarse sandpaper practicing a peculiar skill: rubbing out the most explicit parts of pictures in magazines like Playboy or Penthouse.
Following marked copies provided by supervisors, each woman scratches away the pubic hair and exposed genital areas from the photos on one page. Then she passes the magazine to the next woman, who scratches a patch or two from another page.
Sandpapering these parts out of imported girlie magazines is one way Japan enforces a standard of obscenity that is written in no book of laws or rules but has been widely applied for as long as officials can remember.
That standard, which defines obscenity as graphically depicting human genitalia or pubic hair, in print or on film or videotape, has long been valued by officials for its seeming simplicity.
But it has been less and less simple to apply in recent months, becoming a source of steadily growing embarrassment to police who try to enforce it.
While the standard sometimes blocks distribution of works by serious artists, one newspaper noted recently, it has proved useless in slowing the rampant growth of hundreds of thick monthly "manga" comic books that "depict sexual perversions and violence, including the utter debasement of women, in graphically appalling detail even if pubic hair is not shown."
Recent manga titles on sale in a convenience chain store included "Virgin Shock," "Food for the Bed" and "Let Me Feel It, Baby." One widely followed manga character is a superhero called "Rape Man."
This debasement of women -- often represented by a teen-age girl who starts the sequence wearing Japan's traditional sailor-suit school dress -- has spread to thousands of videotapes available in virtually any neighborhood.
In a society that supports a $31 billion-a-year commercial sex industry -- nearly 1 percent of the gross national product and roughly comparable with the defense budget -- there is a touch of hypocrisy in any police challenge to art photos just because pubic hair or genitalia are shown, several commentators have argued.
Japan's commercial sex industry embraces both the legal and the illegal, ranging from hundreds of ornate "love hotels," where rooms rent by the hour with no questions asked, through "soapland" bathhouses with female attendants who offer more than a bath, to hundreds of young Southeast Asian women who are brought here with promises of housekeeping or office jobs but find themselves trapped for years of virtual slavery in illegal bordellos.
The growing complications of enforcing the unwritten ban on pubic hairs are suggested by a series of recent cases, in which:
* The Tokyo Customs Office held up a shipment of 50 copies of Artnews magazine for 12 days because a photo by Joel Peter Witkin showed the pubic hair of a reclining woman. Then, with no explanation, Customs released the copies. "It is too late," Bernard Krisher, an Artnews representative here, said of the release. "It's like sushi [the Japanese raw-fish delicacy]. If it is left uneaten, it loses freshness. Customs should not lose time judging."
* "Water Fruit," a collection of 54 black-and-white nude pictures of Kanako Higuchi, a popular actress, taken by photographer Kishin Shinoyama, had been on sale for nearly six months and sold 200,000 copies by the time the Tokyo police called in an editor of the Asahi Publishing Co. to issue a "warning." Police said 15 of the pictures showed pubic hair.
* The May issue of Geijutsu Shincho included 28 pages of nude pictures by photographer Nobuyoshi Araki, three of which showed pubic hair. Again, the police issued a "warning."
* Shueisha Inc., a publisher, announced amid the controversy that it would delay the scheduled July publication of a collection of nude pictures of entertainer Rumiko Koyanagi, by photographer Yoshihiro Tatsuki, including some shots that show her pubic hair.
Newspapers and other commentators jumped on the police decision to issue "warnings," rather than to prosecute, as evidence that rapid changes in Japanese attitudes have put the authorities in a bind.
The Asahi newspaper reported that the police decided not to bring obscenity charges, "for the following reasons: 1) the social trend is to accept photos of this type; 2) the artistic value is apparent; 3) the publications are not for children and their readership is limited; and 4) learned men are cautious about bringing criminal charges."
But for officials of Yohan, the importing house that brings foreign girlie magazines to Japan, the standard has not yet changed enough that the several dozen women in Yokohama can put away their sandpaper.
"We do this out of our own will and try to abide by the constitution," said a Yohan spokesman.