Japan has not abandoned hope of playing a role in ending the Persian Gulf war. But it hasn't yet found a way of making a significant contribution. Japan is a logical choice to play mediator. The bulk of its oil comes from the Gulf, and it enjoys close (predominantly economic) relations with both sides. And it has no ideological or political axes to grind.
But the intransigence of both warring parties, coupled with domestic politics , has so far frustrated Japan's initiatives.
''There have been high expectations of Japan to use its unique position with the two countries to make them see the dangers of escalating the war,'' says an American official here. ''But recent events in the Gulf have almost certainly reduced the Japanese ability to contribute to a peaceful solution.''
Middle East governments have been adding their voices to American and European encouragement of the Japanese initiatives. An Arab League mission visited Tokyo in late May. And in a letter delivered to Prime Minister Yasuhiro Nakasone on May 31, Egyptian President Hosni Mubarak appealed to Japan to play an ever more active role in encouraging Iran and Iraq to end their almost three-year-old war. Mr. Nakasone told the carrier of the letter, Egyptian Deputy Foreign Minister Omran el-Shafei, that Japan would continue its efforts.
But meeting Western correspondents over lunch on June 4, Nakasone said Japan and other nations must tread warily to avoid pushing the combatants into ''irrational'' forms of warfare.
He insisted Japan could not act directly as peace mediator between Iran and Iraq, but added: ''We do have sizable economic relations, therefore we do have some bargaining power'' in trying to restrain their actions.
The Japanese leader had high hopes that some form of concerted action could be taken through the just-concluded London summit of seven industrialized democracies. But in this he was disappointed: The Gulf war was briefly discussed but there was no consensus of views.
On June 5, just before Mr. Nakasone left for the summit, there were widespread reports that he had drafted a blueprint for peace, which local newspapers described as ''Japan's first diplomatic initiative since the end of World War II to mediate an armed conflict.''
He reportedly envisaged three steps: a joint appeal for a cease-fire by the London summit, a formal cease-fire agreement, and an eventual troop pullback from the Iran-Iraq border. The possibility of Japanese postwar reconstruction assistance could make such a plan attractive to both Iran and Iraq.
Nakasone's diplomatic initiative would be in keeping with his desire for Japan to be more active in international politics using economic rather than military power.
However, the peace plan immediately ran into strong opposition from Foreign Minister Shintaro Abe and his top ministry bureaucrats. They pointed out that neither the United Nations nor any individual nations had been able to bring the warring parties to the conference table.
Some officials warned that political realities in the Gulf were extremely complicated - with vital big-power interests at stake. They said Japan should choose an easier target - and one with a greater likelihood for success - for launching its ''international diplomat'' role.
Many commentators, however, say an equally important reason for Mr. Abe's opposition is that he is likely to challenge Mr. Nakasone for the leadership of the ruling Liberal Democratic Party this November, and did not want to see a rival cutting into his own territory.