At first blush, Japan's latest tariff reductions appear more cosmetic than real, according to government analysts who spent yesterday pouring over the sketchy details available from Tokyo.

One example cited was the tariff reduction on paper products, especially kraft paper that has extensive industrial uses, which was described as "insignificant." Agriculture experts, meanwhile, noted that Tokyo omitted the key farm products America wants to sell Japan--beef and citrus--from the tariff cuts.

The reduction in duty on tobacco from 35 percent to 20 percent is likely to boost American cigarette sales in Japan somewhat, but industrysources noted that major Japanese restrictions on marketing, advertising and distributions -- known in the trade as MAD -- remain in place.

Furthermore, the reductions in duty on farm products appear concentrated in goods such as raisins and vegetable juices where the major barriers were not tariffs but quotas or inconsistencies in regulations governing the use of additives, government analysts said.

"It looks like no big deal," said one analyst who spent yesterday studying the Japanese announcement.

The clearly skeptical attitude was fostered by a feeling here that the Japanese had failed to live up to previously announced promises to open their markets to American goods. Exactly one month ago, for instance, Deputy U.S. Trade Representative David Macdonald publicly accused Japan of not implementing trade promises it made last May.

"Whether or not these reductions are really worth anything is still open to question," commented one trade official. "They still haven't implemented everything they promised in two previous trade packages."

Macdonald, who just returned from Japan, reportedly told the new Japanese prime minister, Yasuhiro Nakasone, that the Reagan administration wanted some positive sign by Dec. 31 that Tokyo planned to ease tariff and nontariff barriers blocking the sale of U.S. goods.

Tokyo's announcement apparently also is aimed at blunting protectionist pressures in Congress that led to House passage last week of a local content bill on cars that effectively would bar imports of the most popular Japanese models.

Yesterday's tariff reductions thus appear as an attempt to smooth the way for Nakasone's January visit to Washington, during which he will hold his first meetings with President Reagan, who sent the new prime minister a personal letter underscoring the urgency of the trade differences between the two allies and the need for prompt action by Tokyo.

Lionel H. Olmer, Commerce Department undersecretary for international trade, met yesterday afternoon with Japanese Ambassador Yoshio Okawara, presumably to discuss the tariff reductions.

Olmer returned recently from Japan, where he said the United States might have to halt the transfer of high-technology to Japan to force an easing of Japan's "unfair" advantage over American makers.

High-technology was not specifically mentioned in yesterday's tariff reductions, though cuts were promised for calculator parts.

American agricultural officials appeared especially disappointed with their first look at the list of farm goods on which the Japanese said they would reduce duty.

"They are fine," said one. "We're not going to turn them away. But the Japanese have got to address beef and citrus," which are highly protected in Japan even though prices of the domestic product are far higher than American imports would cost.

He noted that tariff reductions in papaya will be somewhat helpful to one state -- Hawaii -- but an increase in shipments of that tropical fruit is "insignificant as far as the total trade picture." Moreover, the real barrier to the sale of America papayas in Japan is not tariffs, but difficulties in getting the product inspected by the Japanese, Macdonald said in a November report to Congress.