"We are ashamed and we apologise," American Ambassador Walter Mondale told the Japanese Foreign Minister, backed up by the commander of US Forces in Japan.
Finally, on Thursday, the furore reached Washington. In a radio interview President Bill Clinton spoke on behalf of the American people. "The United States deeply regrets the incident," he said. "We do not condone any misconduct or any abuse of the Japanese people. We think that anybody who violates any laws should be treated accordingly... But..."
It is that "but" that lies at the root of the whole affair, which began as a local tragedy and is rapidly turning into a major diplomatic embarrassment. Three weeks ago, a 12-year-old girl on the Japanese island of Okinawa was walking home when she was grabbed and bundled into a van by three men. After binding her with adhesive tape, they drove her to a lonely beach and raped her. The suspected assailants were quickly tracked down, and here the complications began. The three suspects are members of the US military, stationed at one of 17 bases on the island. No one, Japanese or American, has ever been in much doubt about their guilt, and the US authorities extended their full co-operation in the investigation.
But as armed forces personnel, the three are protected by a 40-year-old bilateral protocol, the Status of Forces Agreement (Sofa). Once charged, the accused will be turned over to the authorities and subject to the full rigour of Japanese law. But until then, they remain under American, rather than Japanese, custody. The Okinawan police were obliged to request permission from the US base commander to question the three. Every morning last week, they were driven under escort to be presented at the local police station at 9am. Every afternoon, at 4pm, they were driven home again. On Saturdays and Sundays, no interrogation was allowed. If Japanese public opinion needed anything more to fuel its outrage, this was it.
"What does the US commander think the three attackers are?" fumed the habitually circumspect Mainichi newspaper. "Honest to goodness nine-to- five workers?" The governor of Okinawa flew to Tokyo, demanding that the three be handed over unconditionally, and senior politicians, including the Prime Minister, Tomiichi Murayama, seemed to sympathise with him.
The Americans were apologetic, ashamed, and immovable. "As long as they know we are not turning a blind eye to this," President Clinton said, "they know that we have been a good partner and we'll continue to be a good partner."
But the Okinawa incident comes at exactly a time when the nature and necessity of that partnership is coming under increasing scrutiny.
Next week, Japan's ministers of Defence and Foreign Affairs, Seishiro Eto and Yohei Kono, will fly to New York for talks with their American opposite numbers, William Perry and Warren Christopher. The subject of their discussions will be the US-Japan Security Treaty, the 1960 agreement which formed the backbone of American defence policy in the Pacific throughout the Cold War period.
It is under Ampo, as the Treaty is known in Japan, that the Status of Forces Agreement protecting the three suspects is bracketed. Under Ampo, 47,000 troops, plus the US Seventh Fleet, are based in Japan. For a quarter of a century after the war it was the most dangerous and divisive issue in Japanese politics. In 1960, protests over Ampo's renewal provoked riots in the streets of Tokyo. In 1970, it was renewed indefinitely, and the genie was corked in the bottle.
It is the fear of letting it out again that lies behind the American stance on the Okinawan rape case. The post-Cold War changes have had almost no effect on Ampo despite the evaporation of its raison d'etre - the threat posed from the north by the Soviet Union. A Pentagon report earlier this year pointed to the uncertainties posed by China and North Korea, and pledged to maintain current levels of US forces for at least the next 20 years. The commitment to the status quo provoked much high-level criticism, especially in the light of Washington's struggle to prise open Japan's markets to American imports. The 100,000 US troops in East Asia cost $35bn (pounds 23bn) a year, but Tokyo contributes a relatively modest $5bn. Next week's talks were intended to increase its contribution. The danger of incidents like this month's rape is that they will distract attention from the task of balancing the books, and raise questions about the nature of the alliance.