It isn't often that a school textbook triggers an international incident. It would never have happened if the subject were math or Spanish. Facts are facts: one plus one equals two; "yes" equals "si."

But the catalyst for this event was history, and history isn't as cool as math and doesn't translate as easily as a foreign language. Beyond the data and datelines, its facts are often as complex as a billion biographies, as objective as memory, as important as truth, and as hot as politics.

So the news that the Japanese are literally rewriting history was enough to prompt bomb threats in Korea and official protests in China.

It appears that the Japanese Education Ministry ordered changes in the new books for the fall term: changes in emphasis, changes in wording, changes in the way they tell their youngsters about World War II.

As of this fall, the Japanese will have no longer launched "invasions" in China, Southeast Asia and the Pacific. They will have "advanced." In the rape of Nanking, they will have no longer "killed and assaulted" 200,000 Chinese willfully but rather "in the midst of the confusion. . . ."

To understand the impulse of the Japanese Education Ministry, just imagine the difficulty of teaching young children about the brutality, the aggression, the wrong committed by the country they are also expected to love.

To understand the effect of these rewritings on Asians (an estimated 18 million of whom died in World War II), just imagine how we would respond if the Japanese began to teach their children that on Dec. 7, 1941, the Imperial Air Force "advanced" on Pearl Harbor.

The entire incident is in many ways a textbook case. It's a textbook case on the complicated role that history plays in our lives, our understanding of our world, country, families. It's a textbook case on the manipulation of history in the service of politics.

What happened in Japan is not all that unusual. In some way or other, every culture --every country--struggles with its past. To this day there are even heated arguments in this country about whether our early history should be taught as national heroics, led by profiles in courage, or with a more earthy ambiguity.

The more uneasy we are about that past, the more tarnished it seems to us, the more trouble we have telling it to our children. The Japanese have subtly muted their own blame. The official Egyptian guide who led a group of friends to the pyramids three years ago described how they were built by "volunteer labor." For generations we have had extraordinary difficulty teaching children about the realities of slavery or the myths of cowboys and Indians.

As for our present history, I don't envy those publishers who will update the books to include Vietnam. The war is still being fought. The latest battle raging over a monument in Washington is not about architecture, but about the place of the Vietnam War in American history.

The teaching of the past can be an explanation, a judgment, a justification. History can tell sides or take sides. In Argentina and Great Britain, a conflict that grew in part from two sets of history books will be written (I guarantee it) in two separate versions as well as languages. It happens all the time.

But the national autobiography of aggression and guilt is subject to the most peculiar revisions. Germany doesn't rest any more easily on its recent past than Japan. It took until 1962 for German schools to teach children about the death camps. Today there are new "historians" who assault those dead with grotesque rewrites of Nazi reality, calling the Holocaust a hoax.

It is as hard for nations, as it is for parents, to talk about their wrongs. They want respect from the young, and want to instill self-respect in the young. But we can't teach false pride. When we expunge guilt, pretend that it didn't happen, we are tainted by it, committing the ultimate assault on the victims.

Our friendship with our old enemy is due in measure to the way the Japanese acknowledged their aggression as well as their defeat. They told us they were wrong. They told their children they were wrong.

There is a statute of limitations to national guilt. On the whole, few blame the Japan of 1982 for the Japan of 1941. The next generation does not inherit the sins of its parents or grandparents. But it must know those sins. These are the only lasting reparations.