Japan and South Korea have a complicated history, but both face challenges with North Korea and a rising China.
Japan's Prime Minister Yoshihiko Noda, on his first foreign visit to South Korea since assuming his post two months ago, returned ancient royal books stolen during Japanese colonial rule but made no concessions Wednesday on long-running issues, despite rising concerns about China and North Korea.
While demonstrators outside the Japanese Embassy denounced Mr. Noda's visit, Korea's President Lee Myung-bak told him Japan "needs to make active efforts" over demands dating from 35 years of Japanese rule that ended in August 1945.
Well before Mr. Noda got here, however, Japanese diplomats made carefully clear that Japan is not going to budge on the question of compensation for women forced to serve Japanese soldiers as "comfort women" during World War II.
Still, among major mutual concerns are how to deal with North Korea diplomatically and militarily and what to make of the power of China.
"There have been talks about upgrading security cooperation," says Jeff Kingston, director of Asia studies at Temple University's Tokyo campus. "China rising is a common problem. Japan sees opportunities and threats."
As far as the "comfort women" are concerned, says Yutaka Yokoi, director-general for public relations at the Japanese Foreign Ministry, "we have done what we can" - a reference to the treaty signed by Korea and Japan in 1965 that awarded the women token compensation.
Nor, he adds, can Japan renounce its claim to two rocky islets midway between the two countries that are held by Korean forces but long claimed by Japan.
The desire for mutual cooperation, on a free-trade agreement as well as defense and diplomacy, did not cover up the dispute over the contested islets. The Koreans call them Dokdo; the Japanese say they're properly called Takeshima. The islets sit in the middle of what the Koreans call the East …