Late in the San Francisco Peace Conference that negotiated the treaty ending World War II in the Pacific, Prime Minister Shigeru Yoshida of Japan rose to say that his nation accepted "this fair and generous treaty."

Then he launched into the first prominent apology for Japan's aggression of 1931 to 1945, saying: "We have listened here to the delegates who have recalled the terrible human suffering, and the great material destruction of the late war in the Pacific. It is with feelings of sorrow that we recall the part played in that catastrophic human experience by the old Japan.

"I speak of the old Japan," Yoshida said, "because out of the ashes of the old Japan there has risen a new Japan."

That was in September 1951. From that day to this, Japanese leaders have repeatedly expressed regret, sorrow, remorse and apology for that unhappy period. Somehow, however, they have been unable to get those apologies accepted by other people, notably the Chinese and Koreans. Moreover, allegations that Japan has never apologized have intensified recently.

Japan's new prime minister, Shinzo Abe, who is scheduled to visit China and South Korea today and tomorrow, may be confronted with this issue sooner than he might have liked. Unless he resolves it, he will be unable to achieve the aims laid out in his inaugural speech to the Diet, particularly in wanting Japan to be "a country that is trusted, respected and loved in the world, and which demonstrates leadership."

As The New York Times said in a recent editorial: "An ugly, but increasingly distant, history of Japanese aggression and war crimes stands in the way. ... Mr. Abe needs to extricate Japan from this destructive dynamic."

Wikipedia, the online encyclopedia, lists 40 occasions on which a Japanese emperor, prime minister or other leader has expressed remorse for Japan's wartime behavior. Wikipedia cited the Foreign Ministry, press conferences, Diet records, transcripts of meetings with Chinese and Korean leaders, a Tokyo University database and records from the prime minister's office.

Perhaps the most important of those apologies was that rendered by Prime Minister Tomiichi Murayama in 1995 on the 50th anniversary of Japan's surrender. He pointed to what he called the "irrefutable facts of history" and expressed "my feelings of deep remorse and state my heartfelt apology."

That statement, which was approved unanimously by the cabinet that is Japan's executive authority, became the government's official position. Critics before and after have asserted that other apologies were merely personal expressions. Later, Prime Minister Ryutaro Hashimoto and Foreign Minister Yohei Kono asserted that this had been an official statement.

Japan, however, has not gotten these apologies across, for two reasons.

One is Japanese ineptitude in communicating outside of Japan.

The second is that China and South Korea have used the issue to extract diplomatic and economic concessions from Japan. (North Korea is incorrigible on this question and can be ignored.)

Too many Japanese apologies have seemed grudging, weak or diluted by being slipped out amid other statements. With the exception of Murayama's "heartfelt apology," few appear to have had the force of a forthright statement.

On the other hand, Prime Minister Junichiro Koizumi echoed Murayama at an Asia-African summit meeting in Indonesia in 2005 only to have his apology brushed off by China.

A Chinese spokesman, Kong Quan, said: "To express it is one aspect. What's of much more importance is the action. You have to make it a reality."

Abe, the first truly postwar prime minister, has an opportunity now to resolve this issue once and for all. In doing so, he could seek the approval and support of Emperor Akihito, the only one who has the moral and constitutional authority to speak for all of Japan.

This highly visible closure would comprise three elements: