At the end of Foreign Minister Machimura's trip Monday, Japanese diplomats were disappointed that Chinese leaders had refused to meet with him, and he did not get the apology he sought for mobs that pelted Japanese facilities with rocks and excrement.
Still, Japanese Foreign Ministry spokesman Hatsuhisa Takashima said he sees no reason for Japan to downgrade its relations with China.
"The economic relations between Japan and China are so good that the trade volume has already exceeded that of the United States and Japan," he said.
There are signs both countries want to ease mounting tensions. Japan has proposed a commission to address issues that China says triggered the protests. And a Chinese official said Japan's repeated apology for its early 20th century aggression was a step toward healing relations.
Mr. Machimura also reaffirmed Japan's policy of recognizing Taiwan as a part of China - words Beijing wanted to hear.
Some Japanese diplomats indicated they do not know what more China wants from Tokyo to ease the dispute.
Chinese Vice Foreign Minister Wu Dawei told reporters earlier Monday that both countries would need to work further to improve relations.
"Some serious difficulties are emerging in China and Japan relations," he said. "We should say that these problems are the most difficult, and the most serious, problems since the realization of normalized diplomatic relations between China and Japan in 1972."
The two governments are discussing the possibility that Chinese President Hu Jintao and Japanese Prime Minister Junichiro Koizumi will meet later this week at the Asia-Africa Summit in Indonesia.
A series of demonstrations over the past few weeks have sharply reduced the number of Japanese tourists visiting China and raised concerns among Japanese businesspeople, who are pressing their government to resolve the dispute.
The protests have centered on a number of issues, including Japan's approval of textbooks that some Chinese believe gloss over Tokyo's invasion of the country in the 1930s. The topic has become prominent as Japan seeks a permanent seat on the U.N. Security Council, something the Chinese government says should not happen until Japan more fully atones for its past.
Japanese officials say they have apologized many times and hope new discussions might clarify exactly what China wants Tokyo to do.