TOKYO, AUG. 2 -- Not smoothly, not comfortably, but in a series of difficult fits and starts, this consensus-minded country is moving toward a fundamental policy change on an issue that cuts to the core of its culture: the rice supply.

Pushed hard by U.S. Secretary of Agriculture Clayton Yeutter and by the developing countries of Southeast Asia's "rice bowl," the Japanese government seems likely to reverse current law and permit some level of rice imports, perhaps as early as this fall.

Officially, Prime Minister Toshiki Kaifu and his dominant Liberal Democratic Party are still holding to their often-repeated promise that "not a single grain" of imported rice will ever enter Japan. But the politico-industrial establishment that runs the country is evidently setting the stage to reverse this age-old stance.

The impending turnabout on importing rice provides an unusually clear case study of consensus-building, Japan-style. Unlike many major governmental decisions, much of the debate has taken place in public. There has been heavy media coverage of the political back-and-forth, and think tanks, relative newcomers to the policy-making arena here, have played a prominent role.

Japan has been self-sufficient in its staple food since the beginnings of rice cultivation in prehistoric times. Central aspects of the country's social organization and the indigenous religion, Shinto, are built around the rice culture. To this day, the nation's first rice shoots at the beginning of planting season each spring are seeded by the emperor himself.

The national Food Control Law prohibits nearly all rice imports -- even though Japan's tiny, largely unmechanized farms produce rice that costs about six times as much as the global market price.

The import ban stems in part from the disproportionate political clout of farm interests, which have more representation in the national legislature than the farm population would warrant. But it also reflects this island nation's basic sense of insecurity. Completely dependent on foreign sources for its principal fuel, petroleum, Japan has not wanted to turn overseas for its staple food as well.

The status quo on rice has been defended by a three-part alliance quite similar to the "iron triangle" familiar to students of policy making in Washington.

Here, the three corners of the triangle involve farm interests, Liberal Democratic Party members who depend on them for contributions and votes, and bureaucrats in the Agriculture Ministry whose careers are built around supporting domestic rice growers.

But this iron triangle is giving way to a combination of external and internal forces.

As a manufacturing superpower, Japan must maintain good economic relations with the rest of the world. But foreign governments are insisting that Japan start importing rice. Caught between the interests of their foreign customers on one hand and domestic farmers on the other, more and more elements of Japanese society have decided it is better to mollify the rest of the world than to retain the domestic monopoly.

"The most important force for change is what we call gaiatsu, that is, foreign pressure," explained Seizaburo Sato, a political scientist at the University of Tokyo. "When the government feels a need to change policy, it generally goes to the people and says the gaiatsu is strong. People accept that."

Kaifu and his advisers have played the gaiatsu card with considerable virtuosity. After last month's Houston summit, for example, word was leaked to Japanese reporters that President Bush had personally warned Kaifu that Japan would suffer in world trade markets if the ban on rice imports were not lifted.

The pressure from Bush and Yeutter and from other rice-exporting countries has caused a split among the agencies in Kasumigaseki, Tokyo's equivalent of Federal Triangle. While the Agriculture Ministry defends the import ban, diplomats at the Foreign Ministry and international commerce experts at the Trade Ministry are reportedly pushing hard to permit imports from the United States and elsewhere.

Demographic and cultural shifts also work against the rice farmers. With severe labor shortages in the manufacturing and service sectors and with real estate prices skyrocketing, more and more rural Japanese are giving up their farms.

As increasing numbers of Japanese go abroad -- nearly 10 percent of the population is expected to travel overseas this year -- they realize that the domestic price of rice is uncommonly high. Indeed, some hotels in California sell bags of rice in their gift shops for Japanese tourists to take home; such one-bag "imports" are technically illegal here, but common.

Consequently, opinion polls show that most Japanese favor importing some rice, but setting a limit on total imports to keep the domestic supply system in place in case of emergency.

For all that, the policy transition has been rugged. When former trade minister Hikaru Matsunaga, a key figure among the dominant Liberal Democrats, dared to declare publicly six months ago that the ban on rice imports must be ended, he was publicly reprimanded by his fellow cabinet members and forced to call an emergency press conference to recant.

Farm groups and politicians indebted to them angrily denounce anyone who suggests that the time has come to buy rice overseas.

In recent weeks, though, more and more politicians have been willing to risk the farmers' wrath by endorsing rice liberalization -- a sign that change is imminent.

"The foreign pressure, the media, the think tanks and the politicians have really caused a change in the national consensus," says Sato, the political scientist. "When that happens, the policy has to change with it."