Last year, according to both Japanese and Saudi Arabian officials, Japan passed an important economic landmark. It replaced the United States as Saudi Arabia's number one trade partner. Furthermore, Japan is the number one or number two supplier for Kuwait, Oman, Qatar, the United Arab Emirates - and both Iran and Iraq.
This makes Japan now arguably the top trader in the Middle East. But being on top may be a mixed blessing. Clearly any major political disruptions in the Gulf area would do irreparable damage to Japan's economy. Thus it is a major source of concern that Japan is almost totally unequipped to deal with the region on any but strictly economic terms.
In Tokyo voices are being raised in alarm at the shallowness of Japanese foreign policy for the Middle East. Toyoaki Ikuta of the Institute of Energy Economics in Tokyo states flatly: ''If there is a problem in oil supply, of all the industrial nations, Japan would be the hardest hit; (however) Japan has no ability militarily or politically to influence Middle Eastern affairs.''
Paradoxically, it is Japan's seeming disinterest in the political affairs of other nations that provides one of its principal strengths in developing cooperative ventures in today's volatile Islamic world. Despite membership in the club of leading industrial powers, Japan is viewed as a neutral economic partner, interested in profits not ideological influence. One result is that Japan is rarely forced to choose sides in the various conflicts that have embroiled Islamic nations in recent years. It has been able, for example, to maintain its trade with Iran and Iraq throughout the current war without a break. France, by contrast, has been blacklisted by Tehran for dealing with Baghdad.
As their dominance in the region grows, the Japanese may be forced to take some more definite position on political policies. One case in point is the Palestinian issue. Japan has severely curtailed its trade and friendly relations with Israel since the 1973 oil shock. PLO Chairman Yasser Arafat paid a curious visit to Japan in October 1981. Although his visit was billed as ''private,'' he met both with the minister of foreign affairs and then Prime Minister Suzuki.
The Arafat visit gave one important signal to the nations of the Middle East: Japan seemed willing and ready, under the right circumstances, to pursue a foreign policy independent from that of most other nations of the industrialized world - more to the point, independent from that of the US.
In keeping with the economic character of Japanese foreign relations, it is often the so-called ''general trading companies,'' sogo shosha, which serve as the principal Japanese presence in Middle Eastern nations. The sogo shosha account for the bulk of Japanese exports and imports, dominate the capital market, supply the preponderance of Japan's raw materials from abroad, and are arguably the most important single private-sector component of the Japanese economy. They have a strong governmental partner in the Ministry of International Trade and Industry (MITI), which some call ''the second foreign ministry,'' and others ''the real foreign ministry.''
Sogo shosham officials often meet directly with ministry officials in Middle Eastern countries, and for all intents and purposes are the Japanese representatives in the eyes of its officials. This is a practical reality in many cases. For example, Japan is Bahrain's third largest supplier. Seventeen Japanese banks operate in Bahrain, many owned by the sogo shosham. But Bahrain has no embassy in Japan, and Japan has no embassy in Bahrain.
Japan's easy rise to dominance of Middle Eastern trade has been based on a number of interlocking factors. The US has made a concerted effort to reduce its dependence on Middle East oil. Presently, Americans get only 8 percent of their oil imports from the region. Under the Carter administration, confusing and unfavorable tax laws made it difficult for large contracting firms to do business in the region using American expatriates.
Japan has simply moved in to fill the vacuum, creating a pattern of mutually beneficial exchange: Japanese consumer goods and industrial equipment (often subsidized in various ways) for Gulf oil. Here Japan is in the enviable position of being both a good customer and a supplier of desirable goods.
This is not to say that the US has been totally driven out of the Middle East market. The Middle East is, in fact, the only US foreign market that has experienced any significant growth in the past few years. However, the US market share is slipping badly - as much as 30 percent throughout the region by some estimates.
With such an easy market situation it has not been particularly necessary for the sogo shosham and other industrial concerns, or the Japanese foreign service, to recruit individuals with particular expertise in the Middle East. This rather cavalier attitude is in part an outgrowth of Japan's history of foreign relations. Virtually closed to the world from the 17th to the mid-19th century, Japan largely confined its foreign interests to East Asia in the hundred years before World War II. In fact, until the ''oil shock'' of 1973, service ''west of Burma'' was the least desirable foreign posting for private individuals as well as government officials, and not much of an aid to a foreign service career.
There seems to be a notable reversal in this attitude today. Ambassadors and other top-level foreign service staff in the Middle East are drawn from the top ranks of ministry personnel. A few specialists in Arabic are recruited on a regular basis, and young people consider the Middle East an exciting posting.
Still, the Ministry of Foreign Affairs is critically understaffed. The largest Japanese embassies in the region are in Egypt and Saudi Arabia, yet their staffs number only around 22 for each embassy, not counting local support staff. (The entire Foreign Ministry staff throughout the world is only 3,300 - perhaps giving Japan the lowest ratio of foreign service representatives to population of any industrialized nation.)
But like the US in the past decade, Japan's economic requirements are changing. Japan is gradually reducing its energy requirements andm reducing its oil dependency for the energy it does produce. Whereas in 1980 Japan imported 285 million kiloliters of oil to meet its energy needs, projections for 1990 are for only 288 million kiloliters - virtually the same amount. Japan's dependency on foreign oil will thus be reduced from 66 percent of its energy requirements to 49 percent.
Surely this shift will produce dramatic changes in Japan's political relations with Middle Eastern states, which up to now have exerted on Japan none of the pressures to reduce exports and increase imports that have been brought by the US and European countries. It is for this reason that many Japanese urge an increased diplomatic role for Japan, arguing that Japan must have better political insurance for rough times ahead. Although it may reduce its dependence on foreign oil, Japan will find petroleum products from abroad essential to support its civilization.
What is becoming increasingly clear is that the time is rapidly approaching when Japan will be called on to come out of the shadows of the bazaar. Japan has yet to be truly tested in the Middle East. The history of other industrial nations' volatile relations in the region attests to the seriousness of the challenge. It will be interesting to see whether Japan is able to do a better job than its predecessors in Mideast politics.