DEFENSE : Japan May Shift Its Forces to Western Flank : With the Cold War over, Tokyo worries less about a threat from Russia than from North Korea or China.

For decades, Japan has deployed the bulk of its Self-Defense Forces on the northern island of Hokkaido, because the principal threat to its security seemed to be the Soviet Union.

But Japanese defense officials now acknowledge that they are thinking about a significant redeployment of these forces--concentrating them more heavily in the westernmost regions of Japan to guard against possible attack by North Korea or China.

With the end of the Cold War, the nature of the potential military threat to Japan is changing. Japanese defense officials worry less about an attack from Russian territory and more about the dangers posed by their Asian neighbors.

The Defense Agency, in a recent white paper, for the first time cited a potential threat posed to Osaka and Kyoto by new missiles being developed by North Korea, which is also suspected of creating a nuclear arsenal.

Development of a means of delivery for nuclear weapons could have “a critical impact” on Japan, said Haruo Ueno, Defense Agency counselor, in explaining the policy paper to foreign correspondents.

Ueno also expressed an elevated level of concern about China, saying: “We had thought that China’s military power would not become the kind of threat that the former Soviet Union was. But now, China is modernizing its armed forces, especially its naval power, is advancing into the Spratly Islands and recently revised its law concerning territorial waters. We hope China will not become a factor of uneasiness in the security of the region.”

While downgrading Russia from a “potential threat” to an “element of instability,” the Defense Agency’s white paper said the massive Far East forces of the former Soviet Union remain “a cause of uneasiness.”

“I don’t think the will to attack other countries still exists (in Russia), but the capability continues to exist. So we have to watch them,” one senior Japanese defense official, who asked not to be named, said in a recent interview.

Japan also is paying much closer attention to the Korean Peninsula--with an eye toward both the current North Korean regime of Kim Il Sung and a future, reunified Korea.

Japanese defense experts voice less concern than Americans about the danger posed by North Korea’s nuclear program, which one Japanese official said has been “somewhat exaggerated.” “If North Korea increases its military capabilities, we will have to shift (deployments) to the west,” said Atsuyuki Sassa, former director of the Office of Security Planning for the prime minister’s office.

Because of the potential threat from North Korea, a Japanese government official said he believes it is “very important” for American troops to stay in South Korea. If this is not possible, he said, then “we should accept more (American) troops in Japan.”

Korean reunification also worries Japanese defense planners, because any combination of the military strength of North and South Korea--not to mention nuclear weapons--would produce a formidable new military power.

“If the reunification took place this afternoon, (there would be) two armies, one (South Korea) with 615,000 troops and (the other, North Korea) with 1 million troops, total 1,615,000, with possible nuclear weapons,” noted futurologist Alvin Toffler in an interview with the Korea Times last May.

The Region’s Military Muscle

Japan’s defense equation is changing as development of the North Korean and Chinese militaries raises fears over the future. A possible reduction in the U.S. presence is also a factor. Here is the current balance: U.S. Forces in Japan: 21,000 troops and 220 aircraft Japan: 148,000 troops, 170 ships and 440 aircraft North Korea: 930,000 troops, 590 vessels and 790 aircraft China: 2,300,000 troops, 2,1010 vessels and 6,080 aircraft U.S. 7th Fleet: 60 vessels, and 130 carrier-borne aircraft Sources: Military Balance, Jane’s Fighting Ships