The suddent and mysterious Chinese move to reassert its claim over the Taioyutai (Senkaku) Islands ought to send shivers up the spines of American policy planners trying to normalize relations with Peking.

Armed Chinese fishing boats appeared near the disputed islands, also claimed by Japan, at a delicate moment in negotiations over a new Sino-Japanese friendship treaty. At the worst possible moment, the Chinese proved to be either vacillating and divided or clumsy and belligerent.

[The Chinese Foreign Ministry yesterday described the fishing boat dispute as "accidental" and said necessary measures have been taken in the interests of Sino-Japanese friendship, informed diplomatic sources in Peking said, according to Reuter.]

In any case, the incident bodes ill for Carter administration officials who need a long period of quiet in the Taiwan Straits to win domestic political support for the notion of a painless end to formal U.S. ties with Taiwan.

An initial Chinese response to Japanese protests of the incident - that it was just a normal seasonal fishing run - brings smiles even from Communist sources here. The fishermen had blackboards on which they chalked "Tiaoyutai is the territory of the People's Republic of China" of passing Japanese patrol boats.

It is possible that the fishermen were sent by some Chinese faction opposed to improving relations with Japan or determined to embarrass the new administration of Chairman Hua Kuo-feng. Hua undoubtedly has enemies in the government. There are officials in China who would prefer to move toward the Soviet Union rather than toward Japan. Some certainly argue for a more active effort to seize the potentially oil-rich Tiaoyutai, perhaps as in the sudden invasion of the Paracel Islands four years ago.

But there remains little hard evidence of divisions deep enough in Peking or in the coastal provinces to explain such a sudden and provocative act. Communist sources here dismiss the whole notion of an internal power struggle as "more propaganda from Taiwan." Instead, the back the notion that Peking wanted to dramatize to the Japanese before any treaties were signed that Tiaoyutai is Chinese.

To American policy planners, devotion to principle is no more comfort than internal dissension as an explanation for the Chinese move. If the Chinese cannot resist making ill-timed gestures on behalf of a few uninhabited islets, how can they be expected to remain silent about their claim to Taiwan and its 17 million people?

The Chinese acted just as the Japanese were preparing to conclude the peace and friendship treaty with an "anti-hegemony" clause cherished in their jockeying for position against Moscow. Japanese Prime Minister Takeo Fukuda was attemting to rally his Liberal Democratic Party behind such a pact, in the face of objections from a pro-Taiwan minority. Then the Chinese boats showed up last week within the 12-mile limit of the little islands north of Taiwan and the whole timetable was set back.

President Carter has hinted that the wants to molomatic relations with Peking, gaining Chinese confidence and the confidence of U.S. congressional leaders who are worried about the fate of the Nationalist Chinese on Taiwan. Peking had declared it will never abandon its claim to Taiwan, so Carter must be able to convince Americans that the Chinese have no real desire or capacity to invade the island in the foreseeable future.

Like Fukuda, Carter may someday find himself in the midst of delicate talks to win over doubtful Democratic congressional leaders and key Republicans. He may try to head off attempts by potential rivals like Ronald Reagan - a visitor to Taiwan this week - to turn normalization into a potent campaign issue.

An usually long Chinese artillery target practice aimed at the Nationalist-held island of Quemoy, or the sighting of a few Chinese submarines off a Taiwan beach, could abort the whole recognition effort.

Many Chinese diplomats understand this, but Chinese pride or domestic troubles sometimes require that principles be underlined. In the early, shaky days of the Hua administration a year ago, seasoned Chinese diplomat Hao Teh-Ching came to Washington and proceeded to sternly lecture congressmen on the U.S. "occupation" of Taiwan. One of the U.S. experts who attended got a shrug from one of Hao's knowledgeable aides at the end of it, meaning it is likely to happen again.