A tantalizing rumor swept though the thin ranks of North Korea watchers in Asia and America a few days ago, speculating that the "Dear Leader" in Pyongyang, Kim Jong Il, had been placed under house arrest by disgruntled military officers.

The rumor was quickly denied in Seoul, Tokyo and Washington but not before it raised intriguing questions — how did the rumor originate, and why did it make serious analysts of North Korea sit up and take notice?

As with many rumors, it was not clear where this one started. One account said a South Korean intelligence agency planted it in a Japanese news service. Another said the Tokyo news service picked it up carelessly from an advertisement for a novel about North Korea. Whatever the facts, it rippled out swiftly from there.

Even if only a rumor, it underscored how little the outside world knows about the secretive hermit kingdom; North Korea watchers thus grasp at every tidbit that leaks out. More important, it raised the question of "regime change," meaning the overthrow of Kim Jong Il or otherwise seeing him pass from the scene.

Kim probably has more power centralized in his hands than any ruler in the world. So far as is known, however, he has fended off naming a successor even though he is reported to be in ill health as he approaches his 65th birthday on Feb. 16.

Thus, a North Korea run by someone other than Kim would be a genuine mystery to policy-makers in Seoul, Tokyo, Beijing, Moscow and Washington. "The devil we know is better than the devil we don't know," said Alexandre Mansourov, who specializes in Korean affairs at the Asia Pacific Center for Security Studies in Honolulu.

The timing of the speculation over Kim's fate added another twist to the puzzle as it came up just as two negotiations opened. U.S. Treasury officials met last week in Beijing with North Korean officials seeking relief from U.S. financial sanctions. Next week, also in Beijing, U.S. diplomats are scheduled to resume the six-party talks intended to persuade Kim to give up his nuclear weapons. China is the host for the talks, that include diplomats from South Korea, Japan, and Russia.

The U.S. plans to continue the nuclear negotiations even though there is a widening consensus among U.S. officials that Kim has no intention of giving up those weapons, no matter what the U.S. offers.

Evidence for that assessment abounds. The North Koreans have begun, in official pronouncements, to refer to their nation as "a responsible nuclear weapons state." In addition, they have contended that the U.S. is bogged down in a "quagmire" in Iraq, which they apparently think strengthens their bargaining position.

The Congressional Research Service in Washington, which prides itself on dispassionate, nonpartisan analysis, said in a report this month that North Korea has shown an "intent to stage a 'nuclear breakout' of its nuclear program and openly produce nuclear weapons."

William Perry, the deliberate, cautious secretary of defense in the Clinton administration, told a congressional committee in mid-January that if Kim does not give up his nuclear weapons, "the United States may be forced to military action which, while it certainly would be successful, could lead to dangerous, unintended consequences."

Even President Bush seems to have retreated from his onetime insistence that North Korea abandon its nuclear weapons. After North Korea detonated a nuclear device in October, he limited his response to warning North Korea not to transfer nuclear material or technology to others.

South Koreans appear to have accepted North Korea's position, many asserting that Kim will not use nuclear weapons against fellow Koreans. China and Russia are unhappy with a nuclear North Korea but have been unwilling to coerce Kim to give it up.

Japan, emerging from its postwar pacifist shell, has voiced the strongest opposition to Pyongyang's nuclear program. "North Korea's nuclear development," Prime Minister Shinzo Abe said in a policy speech translated by the Kyodo news service last week,"is something Japan cannot possibly tolerate." But he threatened no new action to force Kim to relent.

With this mounting evidence of Kim Jong Il's adamant stance, why does the U.S. continue to negotiate? The main reason, say some U.S. officials, is to keep up diplomatic appearances and to escape blame when diplomacy and the six-party talks fail. Said one official: "They want to keep talking because they think that talking is better than doing nothing."

Richard Halloran is a Honolulu-based journalist and former New York Times correspondent in Asia. His column appears weekly in Sunday's Focus section.