Japan's Prime Minister Yoshihiko Noda, on his first foreign visit to South Korea, returned ancient royal books stolen during Japanese colonial rule but made no concessions on long-running issues. Still, among major mutual concerns are how to deal with North Korea and what to make of the power of China. "There have been talks about upgrading security cooperation," says Jeff Kingston, director of Asian studies at Temple University, Japan Campus. "China rising is a common problem. Japan sees threats and opportunities."