Time was so short, and the cable was so crucial, that Minoru Tamba simply ignored the intricate rules the Japanese Foreign Service has established for the filing of confidential cable traffic. Eschewing code numbers, titles and the telex machine, Tamba wrote out his message by hand at a desk in Washington and sent it by fax to the prime minister and the cabinet back in Tokyo.

That late-summer missive, titled simply Tamba yori, ("From Tamba"), has become known among Japanese diplomats as the "billion-dollar cable" because it helped convince Prime Minister Toshiki Kaifu and his cabinet to commit billions of dollars in Japanese aid to the U.S.-led multinational force in the Persian Gulf.

Tamba, a Harvard-trained diplomat, had been dispatched to Washington to gauge American sentiment toward Japan. What he found, he said later, was "frightening."

"The decisions made in Tokyo about the gulf crisis will determine the next 10 to 20 years of the U.S.-Japan relationship," the cable said. "The gap between what the Americans want and what the Japanese are willing to do is simply enormous."

Since Tamba sent his unusual cable, Japan has committed some $4 billion -- more than any other industrialized country, except the United States -- to the gulf effort, and promised to send a squadron of non-combatant support personnel as well. But the gap in perceptions and understanding between the two nations remains as wide as the ocean that separates them.

Last month, charging that Japan's role in defense in general is too small, the House of Representatives voted, 370 to 53, to withdraw U.S. forces from Japan unless it agreed to cover the full cost of keeping them there. The $4 billion and the budget crisis have for now turned Congress's attentions elsewhere, but many people in Washington predict the issue will arise again.

"So far," said Sen. Lloyd Bentsen (D-Tex.) in a statement yesterday, "Japan has done little {in the gulf} to uphold its interest and even that has been done quite grudgingly." Sen. John Heinz (R-Pa.) said the Japanese need to formulate "a clear idea of what their responsibility to the rest of the Free World is."

Sen. Frank Murkowski (R-Alaska) noted that Japan has no soldiers at risk in the region. The United States and other Western allies, he said, have "put up the maximum resources, namely the human resources, and Japan's excluded." Critics also point out that Japan gets about 60 percent of its oil from the gulf states, compared to about 12 for the United States.

Anti-Japanese feeling has been fed partly by Tokyo's slow response to the gulf situation; it initially offered $1 billion, then late upped the figure to $4 billion. The delay followed a pattern established over the last 40 years, said Henry R. Nau, a George Washington University professor and specialist on Asia. "They react only to our initiatives and our pressure." But underlying economic tensions between the two countries also played a role in the vote.

In Japan, people feel torn between loyalty to and resentment of the United States. "There is a very clear sense here," said political scientist Seizaburo Sato, of the University of Tokyo, "that America is a country in trouble." On the other hand, Sato notes, "most people feel Japan needs the American connection and could be in real trouble if we lost it."

Japanese officials contend that Japan has acted forcefully but not received proper recognition. This week, Yukio Okamoto, a senior Japanese diplomat, visited Washington to discuss details of delivering the $2 billion of aid that Japan has pledged to the multinational forces. (The other $2 billion is to aid allied states in the region.) Eight hundred four-wheel drive vehicles provided by Japan have now arrived in Saudi Arabia, he said, while 125 water and refrigeration trucks are about to be turned over to U.S. forces there.

Between $300 million and $400 million of Japanese money that passed through a joint gulf defense fund is likely to be transferred to the Federal Reserve Bank of New York next week to help offset U.S. transportation costs, he said. Japan has dispatched two freighters to the United States to transport materiel. Japan Air Lines and All Nippon Airways, the country's two largest airlines, have ferried Asian refugees home, while Japanese funds have chartered planes from an American charter company.

Okamoto said Japanese officials have told the U.S. military that they wish to buy hundreds of U.S.-made trucks and computers and ship them to the region for use by U.S. forces there. Japan is also about to buy an $8 million metal-cutting device from a Colorado firm to be used in Middle East construction.

Okamoto said Japan intends to finance and build temporary quarters for U.S. soldiers now living in tents in Saudi Arabia. It also intends to supply several thousand TV sets and videocassette recorders for entertainment purposes. In most cases, the purchases will be made in the United States, he said, which should silence any criticism that Japan is attempting to realize commercial advantage through its programs.

But whatever the size or form of Japan's ultimate contribution, some American analysts believe that it will not be a key factor in crafting the long-term future of the relationship. Paul Kreisberg, senior associate at the Carnegie Endowment for International Peace, predicted that ties will remain rocky if there is still a wide trade deficit and Japanese investors continue to buy American companies and real estate in large quantities.

Kaifu has struggled to find a political balance between Japan's traditional partnership with the United States and the urge -- particularly strong among people born after World War II -- to see Japan break free of U.S. control on some matters.

A key basis for Kaifu's high standing in opinion polls has been his foreign policy initiatives -- and particularly his friendship with President Bush. But the prime minister has been criticized in Japan recently for being too friendly with the American president.

When he decided that Japan would contribute money to the allied effort in the Middle East, Kaifu called Bush about the plan before he told the Japanese people. A hot political joke of the moment says Kaifu has replaced his push-button phone with a new model called the "Bush-button" phone.

In one sense, Japan has become a victim of its own economic success. As a global economic superpower, the country suddenly finds that it is expected to play a global political role as well. "This has been a hard idea for our people to accept," said Kazuo Aichi, a member of the Diet, or parliament, from Sendai province. "When I tell my constituents that our international economic reach gives us international responsibilities, they just don't want to hear me."

Kaifu already seems to have gone beyond what the general public supports. An opinion poll taken in Japan by the Asahi Shimbun newspaper late last month showed that 67 percent thought Kaifu was wrong in proposing to send members of Japan's military to the gulf -- even though Kaifu said they would fill only non-combat roles. An Asahi-commissioned poll of U.S. opinion, in contrast, found that 77 percent of the Americans surveyed felt Japan's contribution to the gulf effort has not been enough.

While the $4 billion has satisfied many American critics, a number of analysts feel that if hostilities break out and Americans begin dying, Japan's role will again come under intense fire for not putting its own people at risk.

Kaifu is planning something that could change that, however. The Diet will meet in special session next month to consider his proposal to send Japanese military personnel to the gulf in some non-combatant capacity. There is a chance, albeit small, that the plan will be voted down.

One reason that Japan has been reluctant to commit to the gulf effort is the nation's "Peace Constitution," which declares that "the Japanese people forever renounce war as a sovereign right of the nation." The constitution -- particularly its "no war" clause -- is extremely popular in Japan.

Nearly all Japanese know that this constitution was written by Americans and imposed on the country by U.S. fiat shortly after World War II; this fact is not so familiar to Americans. "The sad reality," political scientist Jun Eto wrote recently in a Japanese opinion journal, "is that our so-called 'Peace Constitution' is not respected by any other country in the world -- including the U.S., which wrote it."

Reid reported this article from Tokyo, Burgess from Washington.