The adage "the enemy of my enemy is my friend" assumes special significance in ongoing talks between Japan and North Korea. Who would imagine these two - the former a powerful anti-communist state driven by capitalism, the latter an absolute dictatorship over a decaying socialist system - cosying up to one another?
Quite aside from differences in forms of government, North Korea and Japan harbour centuries-old complexes of hatred that have intensified since the end of Japanese rule over the Korean peninsula in 1945. Japan's alliance with the United States and enormous dealings with South Korea would seem to have precluded any moves towards reconciliation.
Lately, however, Japan and North Korea share a common cause that accounts for why Pyongyang is, unexpectedly, ready to talk about Japanese citizens who the Japanese believe remain in the North many years after they were kidnapped from Japanese soil.
The world knows about the cases of 13 people who North Korea admitted in 2002 to have spirited from Japan, but Japanese believe there are many more.
Why would North Korea suddenly assent to discussing the issue? And why would Japanese officials be so eager to talk to the North Koreans? The answer is China. Neither North Korea nor Japan can stand for China's staking out positions that present a clear danger to their territorial integrity. Both are upset by China's growing strength - and the disturbing tendency of the Chinese to assert their interests.
North Koreans have always expressed degrees of outrage and alarm over China's efforts to tell them what to do. Lately, the Chinese have been pressuring North Korea not to conduct a fourth nuclear test and not to go on investing badly needed funds in fashioning a nuclear device small enough to attach to a long-range missile. Far better for the North Koreans to invest in an economy that now ranks among the region's most backward. North Korean leaders will have none of that.
For Japan, the Chinese threat focuses on China's challenge to the Japanese grip on the island cluster known as the Senkakus to the Japanese and the Diaoyus to the Chinese. Chinese claims have become ever more strident as Chinese warplanes fly over the islands and Chinese fishing and "research" vessels stage forays around the islands. The Japanese scramble their own planes in response, and Japanese coastguard vessels try to shoo Chinese boats away.
Chinese commentators have long since staked a theoretical claim to Okinawa, the southernmost island prefecture that includes the Senkakus. They note that Okinawa, in the days of the Ryukyu kingdom, swallowed up by Japan in 1879, paid homage to China long before the Japanese intruded. This argument holds that Okinawa should be a protectorate of China.
Thus, for strategic and geopolitical reasons, North Korea and Japan are drawn to one another in an embrace, in which their leaders are ready to sublimate Japanese Prime Minister Shinzo Abe's pilgrimages to the Yasukuni Shrine, honouring Japanese war dead, including war criminals. "North Korea for Abe is a way for Japan to regain its footing in the region," says Tony Namkung, a Korean-American with long experience in negotiating with the North.
Americans and South Koreans may wonder what to make of the talks. For Japan and North Korea, China represents a threat that both need to counter - if necessary by cooperating with each other.
Journalist Donald Kirk is the author of three books and numerous articles on Korea