Kingo Machimura is a conservative, nationalistic member of the Japanese parliament who has never lived comfortably with the fact that Japan's constitution was imposed by the American post-war occupation forces.

"It was made almost without the hands of the Japanese touching it," Machimura recalls with a trace of emotion in his voice. "This is something that is unforgivable for the Japanese people."

A substantial minority of the ruling Liberal Democratic Party holds similar views, and it has succeeded this fall in making revision of the foreigners's constitution a major party issue. For the first itme in nearly a decade, constitutional revision is being seriously discussed within the party.

Hidekazu Kawai, a Gakushuin University political science professor, calls the controversy "much ado about nothing" and predicts little will come of it, although he has documented steps taken by the occupation forces in the late 1940s to write Japan's new constitution.

The reason for the drive is partly emotional, a desire by Machimura and other party elders with long memories to right a painful wrong.

But what has given them a fresh platform is Japan's new worry about national defense.

The post-war constitution renounced war forever.Despite that, Japan has built up a sizable military force, but it rests on shaky legal underpinnings and the revisionists such as Machimura think it is time to have a lawful army.

"The preface of the constitution says that the Japanese people pray for eternal peace and so we must rely on the justice of nations that want peace," observes Machimura. "Considereing the present situation, this is a kind of dream."

The "present situation," as Japan's more hawkish legislators see it, is that the United States has lost military superiority over the Soviet Union and might not be able to defend Japan, especially if it was fighting in the Middle East or Europe when Japan needed help.

This sentiment was reenforced by two recent events. One was the Soviet invasion of Afghanistan, which strongly affected public opinion here. A second was the steady buildup of Soviet military forces on small islands north of japan. Some Japanese believe these troops could turn into an invasion force.

The hawks believe that Japan must be able to defend itself independently, relying on the United States and the mutual security treaty merely for strategic nuclear protection.

The constitutional muddle that Machimura and his colleagues want to clear up was a legacy of the American occupation forces led by Gen. Douglas MacArthur. They first insisted that Japan renounce war and military force forever and succeeded in forcing adoption of an article that did just that in 1947.

A few years later, with the cold war settling in and a war raging with communists in Korea, MacArthur changed his mind and got Japan to extablish a 75,000-member police reserve force, which became the forerunner of the present Self-Defense Force of about 240,000 troops.

A broad Japanese consensus now accepts the Self-Defense Force as a fact of life, and a generation of political leaders has chosen not to face the legal muddle squarely by revising the constitution.

The Liberal Democratic Party in 1955 wrote a platform declaring Japan has the right to an independent constitution, but discussion of it pretty much ended that year. The issue arose again in 1972, but nothing was ever done to replace the "MacArthur constitution," which has survived intact without a single amendment.

Discussion was considered taboo until this fall when an outspoken Cabinet member, Justice Minister Seisuke Okuno, bluntly appealed for public support of an "independent constitution."

"The present constitution was worked out at the instruction of the occupation forces, and we could not make a decision on any article without the consent of the occupation forces," Okuno declared.

His remarks touched off a furious debate and placed Prime Minister Zenko Suzuki in an embarrassing position. Suzuki eventually responded with a decision that it was acceptable for his party to discuss the issue but that he had no intention of pushing for a revision.

Suzuki and a probable majority in his party are opposed to raising the highly emotional issue of revision, and even Machimura agrees there is little likelihood of a major change being brought to a vote in the present mood.

Nevertheless, a special party committee has been established to deliberate the merits of revision. It meets regularly, usually with less than a majority present. And the Japan Socialist Party, which still argues for a position of unarmed neutrality, considers the latest moves to endorse and legitimize a military force so important that it has made opposition to revision its major 1981 task.

Toshiki Kaifu, a lower house member who speaks for younger legislators, says 80 percent of party collegues in his age group oppose revision now. The Self-Defense Forces are acceptable to Japanese people without a revision, he argues, and even opposition parties are swinging around to that view.

The pragmatic solution, Kaifu contends, is merely to go along with what has worked rather well so far. "This consititution has kept Japan at peace and has made the people more wealthy day by day," he said. "There is no reason to change it now."