An article yesterday incorrectly identified the type of bomber used to drop atomic bombs on the Japanese cities of Hiroshima and Nagasaki in 1945. It was a B-29. (Published 12/4/94)

TOKYO, DEC. 2 -- It started out as small as a postage stamp, but the latest transpacific dispute over the end of World War II could well blow up into a major new source of ill feeling between the United States and Japan.

The U.S. Postal Service plans to issue a stamp bearing a full-color portrait of the atomic bomb's mushroom cloud, its caption clearly indicating the stamp is intended to depict the nuclear bombings of Hiroshima and Nagasaki. The stamp is one of a set of 10 commemorative issues planned for next year to mark the 50th anniversary of the end of the war.

But Japan's government said today that it would ask the United States to reconsider, while politicians, pundits and ordinary people here expressed surprise and outrage.

"I cannot understand why they {would} make a stamp to commemorate a horrible instance of human suffering," said Hiroshi Harada, director of the Peace Museum at Hiroshima.

"It is truly terrible that they could be so heartless," said Hiyoshi Motoshima, the mayor of Nagasaki. "Beneath that mushroom cloud, hundreds of thousands of noncombatant women and children were killed or injured on the spot... . The atomic blast was a case of indiscriminate massacre."

The anger over the stamp seems likely to augment the growing discomfort here over the controversy in the United States regarding the upcoming Smithsonian exhibit on the atomic bomb. Already, officials in Hiroshima and Nagasaki have said they may reconsider their previous agreement to cooperate with the Smithsonian.

U.S. diplomats said the stamp would make a touchy situation more difficult.

"The whole idea that the 50th anniversary could be a time for forgiveness and mutual understanding looks further and further away all the time," a U.S. official said.

In Washington, U.S. Postal Service spokesman Robin Wright said the Citizens' Stamp Advisory Committee, in coordination with historians from the State and Defense departments, began working in the late 1980s on a five-year series of stamps commemorating World War II events.

The series, Wright added, "is intended to philatelically and chronologically mark the significant events, trends and outcomes of the world at war... . We are not making a value judgment on any of those events. With regard to the stamp in question, we would be remiss in omitting such a watershed and historically critical event as the use of the atomic bomb."

Reaction here was particularly sharp against the caption at the bottom of the mushroom cloud picture. It declares, "Atomic bombs hasten war's end. August, 1945."

While almost all Americans look on World War II as a just cause for their country, Japanese feelings are more complex and conflicted.

Nationalists, including some prominent politicians, still justify Japan's attacks on Asian countries and the sneak attack on U.S. ships docked at Pearl Harbor, Hawaii. But most Japanese today seem to agree that their nation's aggressive military steps were unjustified.

On the issue of the atomic bomb, however, the Japanese generally seem to feel it was the United States that was in the wrong. They argue -- as Mayor Motoshima of Nagasaki did again today -- that the potent new weapon was not necessary to force Japan to surrender, and that the United States used the bomb to gain the upper hand vis-a-vis the Soviets in postwar geopolitics.

Thus, the new U.S. stamp tends to make the Japanese as angry as Native Americans might be if the Post Office issued a stamp honoring an Army victory at the 1890 Battle of Wounded Knee, in which 300 Sioux, many of them women and children, were massacred; or as angry as African Americans might be if a new stamp honored segregationist Sheriff "Bull" Connor and his deputies in Birmingham, Ala., during the campaign for civil rights.

Foreign Minister Yohei Kono said Japan, "as the only country ever to have been attacked with the atomic bomb," has an obligation to convey its regret about the stamp to the United States. Prime Minister Tomiichi Murayama told reporters that "this stamp strikes a nerve with the Japanese people, and we will convey this sentiment" to U.S. officials.

The dispute comes on top of frayed feelings across the Pacific because of the difficulties surrounding the Smithsonian's plan for a 50th anniversary exhibit next year featuring the Enola Gay, the B-52 bomber that dropped the Hiroshima bomb, the first atomic weapon used in combat.

Officials at Hiroshima and Nagasaki had agreed to cooperate with the Smithsonian and lend materials. Among the items to be loaned were clothing and personal belongings of children who were killed by the blast, including a shredded school uniform and a grotesquely burned school lunch box.

But U.S. veterans protested the Smithsonian's plans. Under pressure, museum officials negotiated with veterans' groups. The result was a new plan for the exhibit that focuses much more on Japanese steps that caused the war, and less on Japanese suffering.

Under the new plan, the Smithsonian says it no longer wants to display the school uniform and lunch box.

Japanese officials have taken that to mean the Smithsonian is planning an exhibit that will seek to legitimize use of the atomic bomb. In a letter this fall to U.S. officials, Hiroshima Mayor Takashi Hiraoka said "the mentality which justifies not only the dropping of the atomic bomb, but also war itself, makes us, the citizens of Hiroshima, angry and sad. ... It is important that people in the world know the reality of the destruction left by the dropping of atomic bombs ... and to recognize the inhumanity of nuclear weapons."

CAPTION: Japanese reaction is particularly sharp against the caption of the planned stamp, one of a series commemorating World War II events.