Honoring the Emperor - and Japan. Presence of world leaders at funeral is tribute to nation's expanding global role. ALL EYES ON TOKYO

THE world is gathering in Tokyo this week. Delegations from 154 nations will attend the funeral of the late Emperor Hirohito tomorrow, while millions more across the globe will watch on television.

The foreign attendance at the ceremony, by far larger than any previous funeral for a world figure, is less a tribute to the monarch than a recognition of the rising power of the nation he reigned over for more than 62 years.

The presence of the foreign leaders - 55 of them heads of state, including presidents and kings - reflects Japan's expanding role in world affairs.

``Of course it is because of Japan's economic power,'' says Shoichi Oikawa, senior editorial writer for Yomiuri Shimbun, Japan's largest daily paper.

Few would deny that Japan's role is defined almost entirely by the fact it is now the world's second largest economy. Its massive trade surplus has made Japan the world's largest creditor nation and a growing source of investment. Japanese industry, once denigrated as a mere imitator, now can claim to be a technological leader second only to the United States.

Japan's economic strength undoubtedly accounts for the substantial presence at this funeral of leaders from Africa and Latin America - places not usually associated with this Asian power. ``They want to have economic aid,'' Mr. Oikawa says, a blunt statement of the reality that Japan is now the largest source of foreign assistance to the third world.

Prominent African leaders - from countries such as Nigeria, Ghana, Kenya, Zaire, and Zambia - are here. Brazil, the Latin country with the closest ties to Japan, has sent its President. The Japanese foreign minister will host lunches with counterparts from Central America and Africa.

But the funeral is also a reminder that Japan is first of all an Asian power, an economically dominant force in the lives of peoples from Korea to Pakistan. The Japanese presence is strongest in East Asia - drawing leaders like Indonesian President Suharto, Philippine President Corazon Aquino, and Singapore's Lee Kuan Yew to Tokyo this week. But it is growing in South Asia as well, signaled by the arrival of Pakistan's new prime minister, Benazir Bhutto. Still for the Japanese, the most important relationship remains with their postwar protector and ally, the United States. The decision of President Bush to attend the funeral - so early in his term - is seen here as a reassuring statement of America's commitment to that alliance.

French President Fran,cois Mitterrand represents for Japan the more distant but substantial links with the European Community.

Japanese officials were hoping that Soviet President Mikhail Gorbachev would use the funeral as an opportunity for a first-time visit by a Soviet leader to Japan. But they are pleased with the arrival of close Gorbachev ally Anatoly Lukyanov, first deputy chairman of the Presidium of the Supreme Soviet.

The decision of some nations to send less prominent leaders has also served to remind Japan that memories of World War II, and questions about Emperor Hirohito's responsibility for that, remain potent.

In past days, for example, the Chinese government and media have reacted harshly to the comments made by Prime Minister Noboru Takeshita that it was up to future historians to judge whether Japan was the aggressor in that conflict.

Indeed, it is the memory of Japan's previous attempt to grab a major share of world power that feeds the Japanese inclination to remain a one-dimensional, economic power. When Emperor Hirohito ascended to the Chrysanthemum Throne in 1926, Japan was also making its weight felt as the first non-Western power. But prewar Japan sought to couple its industrial prowess with military might, a combination that fueled the imperial aggression which culminated in the Pacific War.

Postwar Japan, even as it has gained great economic muscle, has shied away from asserting itself.

``There is a general sentiment in Japan that we should not play a political role in international affairs,'' explains Mr. Oikawa. ``For a long time, for the Japanese public, acting in political affairs meant being a military power. But now Japan must act - of course by nonmilitary means.''

The greatest impact of Hirohito's funeral may be to encourage that sentiment in Japan.