Japan's abhorrent practice of enslaving women to provide sex for its troops in World War II has a little-known sequel: After its surrender -- with tacit approval from the U.S. occupation authorities -- Japan set up a similar "comfort women" system for American GIs.

An Associated Press review of historical documents and records shows American authorities permitted the official brothel system to operate despite internal reports that women were being coerced into prostitution. The Americans also had full knowledge by then of Japan's atrocious treatment of women in countries across Asia that it conquered during the war.

Tens of thousands of women were employed to provide cheap sex to U.S. troops until the spring of 1946, when Gen. Douglas MacArthur shut the brothels down.

The documents show the brothels were rushed into operation as American forces poured into Japan beginning in August 1945.

"Sadly, we police had to set up sexual comfort stations for the occupation troops," recounts the official history of the Ibaraki Prefectural Police Department, whose jurisdiction is just northeast of Tokyo. "The strategy was, through the special work of experienced women, to create a breakwater to protect regular women and girls."

The orders from the Ministry of the Interior came on Aug. 18, 1945, one day before a Japanese delegation flew to the Philippines to negotiate the terms of their country's surrender and occupation.

The Ibaraki police immediately set to work. The only suitable facility was a dormitory for single police officers, which they quickly converted into a brothel. Bedding from the navy was brought in, along with 20 comfort women. The brothel opened for business Sept. 20.

"As expected, after it opened it was elbow to elbow," the history says. "The comfort women ... had some resistance to selling themselves to men who just yesterday were the enemy, and because of differences in language and race, there were a great deal of apprehensions at first. But they were paid highly, and they gradually came to accept their work peacefully."

Police officials and Tokyo businessmen established a network of brothels under the auspices of the Recreation and Amusement Association, which operated with government funds. On Aug. 28, 1945, an advance wave of occupation troops arrived in Atsugi, just south of Tokyo. By nightfall, the troops found the RAA's first brothel.

"I rushed there with two or three RAA executives, and was surprised to see 500 or 600 soldiers standing in line on the street," Seiichi Kaburagi, the chief of public relations for the RAA, wrote in a 1972 memoir. He said American MPs were barely able to keep the troops under control.

Though arranged and supervised by the police and civilian government, the system mirrored the comfort stations established by the Japanese military abroad during the war.

Kaburagi wrote that occupation GIs paid upfront and were given tickets and condoms. The first RAA brothel, called Komachien — The Babe Garden — had 38 women, but due to high demand that was quickly increased to 100. Each woman serviced from 15 to 60 clients a day.

American historian John Dower, in his book "Embracing Defeat: Japan in the Wake of WWII," says the charge for a short session with a prostitute was 15 yen, or about a dollar, roughly the cost of half a pack of cigarettes.

Kaburagi said the sudden demand forced brothel operators to advertise for women who were not licensed prostitutes.

Natsue Takita, a 19-year-old Komachien worker whose relatives had been killed in the war, responded to an ad seeking an office worker. She was told the only positions available were for comfort women and was persuaded to accept the offer.

According to Kaburagi's memoirs, Takita jumped in front of a train a few days after the brothel started operations.

"The worst victims ... were the women who, with no previous experience, answered the ads calling for `Women of the New Japan,'" he wrote.

By the end of 1945, about 350,000 U.S. troops were occupying Japan. At its peak, Kaburagi wrote, the RAA employed 70,000 prostitutes to serve them. Although there are suspicions, there is not clear evidence non-Japanese comfort women were imported to Japan as part of the program.

Toshiyuki Tanaka, a history professor at the Hiroshima Peace Institute, cautioned that Kaburagi's number is hard to document. But he added the RAA was also only part of the picture — the number of private brothels outside the official system was likely even higher.

The U.S. occupation leadership provided the Japanese government with penicillin for comfort women servicing occupation troops, established prophylactic stations near the RAA brothels and, initially, condoned the troops' use of them, according to documents discovered by Tanaka.

Occupation leaders were not blind to the similarities between the comfort women procured by Japan for its own troops and those it recruited for the GIs.

A Dec. 6, 1945, memorandum from Lt. Col. Hugh McDonald, a senior officer with the Public Health and Welfare Division of the occupation's General Headquarters, shows U.S. occupation forces were aware the Japanese comfort women were often coerced.

"The girl is impressed into contracting by the desperate financial straits of her parents and their urging, occasionally supplemented by her willingness to make such a sacrifice to help her family," he wrote. "It is the belief of our informants, however, that in urban districts the practice of enslaving girls, while much less prevalent than in the past, still exists."

Amid complaints from military chaplains and concerns that disclosure of the brothels would embarrass the occupation forces back in the U.S., on March 25, 1946, MacArthur placed all brothels, comfort stations and other places of prostitution off limits. The RAA soon collapsed.

MacArthur's primary concern was not only a moral one.

By that time, Tanaka says, more than a quarter of all American GIs in the occupation forces had a sexually transmitted disease.

"The nationwide off-limits policy suddenly put more than 150,000 Japanese women out of a job," Tanaka wrote in a 2002 book on sexual slavery. Most continued to serve the troops illegally. Many had VD and were destitute, he wrote.

Under intense pressure, Japan's government apologized in 1993 for its role in running brothels around Asia and coercing women into serving its troops. The issue remains controversial today.

In January, California Rep. Mike Honda offered a resolution in the House condemning Japan's use of sex slaves, in part to renew pressure on Japan ahead of the closure of the Asian Women's Fund, a private foundation created two years after the apology to compensate comfort women.

The fund compensated only 285 women in the Philippines, South Korea and Taiwan, out of an estimated 50,000-200,000 comfort women enslaved by Japan's military in those countries during the war. Each received 2 million yen, about $17,800. A handful of Dutch and Indonesian women were also given assistance.

The fund closed, as scheduled, on March 31.

Haruki Wada, the fund's executive director, said its creation marked an important change in attitude among Japan's leadership and represented the will of Japan's "silent majority" to see that justice is done. He also noted that although it was a private organization, the government was its main sponsor, kicking in 4.625 billion yen, about $40 million.

Even so, he admitted it fell short of expectations.

"The vast majority of the women did not come forward," he said.

As a step toward acknowledging and resolving the exploitation of Japanese women, however, it was a complete failure.

Though they were free to do so, no Japanese women sought compensation.

"Not one Japanese woman has come forward to seek compensation or an apology," Wada said. "Unless they feel they can say they were completely forced against their will, they feel they cannot come forward."