Japan has pushed Chinese diplomats for more information about Beijing's search for natural gas in areas of the ocean the two countries both claim. Japanese diplomats proposed the two governments take steps to improve ties.
Among the topics raised in the six hours of talks in Tokyo were China's search for natural gas in areas of the East China Sea that straddle the line midway between the two countries.
Akira Chiba, Japanese Foreign Ministry spokesman, said Monday the Chinese were pressed to provide details. "This is something that we have been asking them for a while," he said. "But the Chinese side said that they have taken note of the interest of the Japanese side and that they will bring it back to their home country and study about it."
Japanese officials call the talks, the third round of the year, "very constructive."
Another general policy dialogue will be held next month in Beijing. Mr. Chiba terms the desire to continue talking a thaw in the chilly relationship between the two nations. "And, I guess, taken the present Sino-Japanese relations, a thaw is a very important thing that would happen," he said.
Japanese diplomats Monday also proposed that the two governments work on ways to continue the thaw, including a possible visit to China by Japan's foreign minister. But the diplomatic temperature has a way to go before it really gets warm.
Japan opposes Europe's proposed lifting of an embargo on arms exports to China. The Chinese are upset about what they perceive as a lack of contrition from Tokyo for its invasion in the early 20th century.
That history amplifies territorial disputes.
A private Japanese research vessel arrived Sunday at one set of disputed islands - Okinotori-shima. The two-day survey of the remote outpost, funded by a conservative foundation, comes in response to calls by right-wing politicians in Japan to build commercial and research projects on the island.
China contends Okinotori-shima, 1,700 kilometers south of Tokyo, is just a big rock and not an island.
The distinction is important because if the outcroppings are not considered islands, then the surrounding waters would be considered international territory and China and other countries would have the right to explore for natural resources in the area.
Japan's Transport Ministry on Monday confirmed it plans to install a radar system on a platform across two of the reefs to monitor shoreline erosion. But ministry official Toru Noda acknowledges that the system will also be able to track ships within 20 kilometers of the area.
Mr. Noda stresses that the ministry is most eager to use the radar to identify boats that damage coral reefs around the outcroppings.
A night-vision camera system was activated last month on the island after repeated sightings of Chinese research ships in the area.