Political maelstrom awaits Nakasone at home after US visit. Japan's premier faces tough fight to increase domestic spending

A crowded political agenda awaits Prime Minister Yasuhiro Nakasone in Tokyo as he prepares to carry out promises made to President Reagan and the United States Congress. After his whirlwind trip to Washington, the Japanese premier has two days on this sun-kissed island to play golf and collect his thoughts before plunging back into Tokyo's political maelstrom.

The most important promise is to increase domestic demand in order to achieve a historic change in Japan's economy, from export-driven growth to import-inducing growth. Leading Western and Japanese economists agree that this is the only way in which Japan can reduce its huge export surpluses, which topped $100 billion during the last fiscal year. Over half of that surplus - $52 billion - was with the US.

Meeting with journalists, Mr. Nakasone recited a haiku poem he composed as an expression of his determination. Nightfall And still the cicadas shrilly sing As long as they have life.

A cicada's life is just for summer, but he sings as long as there is life in him. Nakasone, whose term expires Oct. 31, said he would keep singing ``like the cicadas.''

The first step will be to compile a supplementary budget of $34.68 billion, which will concentrate on public works and social spending (sewers, housing, and the like).

The ruling Liberal Democratic Party has already begun work on this, but Nakasone said the government could not be formally associated with it until this year's $382 billion budget has passed the upper house of the Japanese parliament (expected May 21).

Nakasone promised President Reagan and the US Congress that the supplementary budget represented ``real money'' and would not be offset by reductions in the next year's budget.

The powerful Ministry of Finance, which with Nakasone's approval has imposed budgets of Draconian austerity on Japan for the past five years, resists the idea of deficit financing, which the supplementary budget would do.

Rule by consensus is the Japanese way, and Nakasone will have to do some behind-the-scene arm twisting to get the results he wants.

He claims not to have deserted the austerity budgets altogether. Nakasone said Saturday he will have a ``two-sworded policy.'' By this he means he plans austerity for most budget items, but a determined push on public works, social spending, and other items intended to stimulate economic demand.

Nakasone must also work out the specifics of a promised $30 billion aid package - $10 billion already committed to the World Bank and another $20 billion in untied aid for developing countries in Latin America, Asia, and Africa.

A billion-dollar special fund to purchase government equipment from non-Japanese sources will be fleshed out. US-made Cray supercomputers will probably be bought from this fund.

In mid-May, US and Japanese officials will meet to compare data on semiconductor chips. The punitive 100 percent tariffs President Reagan imposed April 17 will be lifted if there is clear evidence that US exports to Japan have increased, and that Japanese exports to the US have decreased along with exports to third-country markets (principally Taiwan and Hong Kong).

This was one of the most contentious issues in Nakasone's talks at the White House, and he is anxious that the sanctions be lifted as soon as possible.

Meanwhile the political storm roused in Tokyo by the five-percent sales tax issue just before Nakasone left for Washington is likely to revive as soon as parliament's recess ends May 5.

Opposition parties clamor for Nakasone's resignation, since he was the chief advocate of the sales tax which ultimately had to be abandoned in order to get the lower house to pass this year's budget.

However, Nakasone has been careful to associate his three potential successors - Finance Minister Kiichi Miyazawa, former Finance Minister Noburu Takeshita, and former Foreign Minister Shintaro Abe - with the sales tax also. None of them is strong enough to shove Nakasone aside and become prime minister on his own.

The Liberal Democrats have a comfortable majority in parliament. So long as they remain united, there is no way the opposition parties can bring Nakasone down.

Japanese and foreign observers agree that Nakasone has been politically weakened by the sales tax issue. But a prime minister can not be brought down easily unless he is deserted by his own party. Nakasone is unlikely to have his term renewed beyond Oct. 31, by which time he will have served five years. But until then he seems reasonably secure.

``I will decide when to step down,'' he told reporters firmly.