Japanese Prime Minister Yasuo Fukuda has held talks in Beijing with his Chinese counterpart, Wen Jiabao.
The two PMs met amid a thaw between Beijing and Tokyo
Both parties indicated that ties between the two countries were improving, saying "spring has come".
They discussed increasing co-operation on environmental issues and nuclear fission, but did not resolve a dispute over maritime gas fields.
The talks came on the first full day of Mr Fukuda's visit to China - his first since taking office in September.
"Prime Minister Fukuda said the spring has come in our relations and, after two-and-a-half hours of talks, I truly feel that the spring of China-Japan relations has arrived," Mr Wen told a joint news conference.
Mr Fukuda said that China and Japan had never had more influence or responsibilities in Asia and the world, and that it was time to overcome problems in their relationship.
The visit is the latest indication of a thaw in relations after decades of rivalry and historical tensions.
In recent months a Chinese warship dropped anchor in Tokyo Bay for the first time since World War II.
Japan has expressed concern over China's problems with pollution
The leaders discussed increasing co-operation on a range of issues, including developing ways of tackling climate change.
Under a new agreement, about 50 Chinese researchers will be invited to Japan every year for the next four years to train in the science of combating climate change.
However there was no agreement on a bitter dispute over rights to gas fields in the East China Sea.
The ministers pledged to continue negotiations but Japanese Foreign Minister Masahiko Komura said that there were still major differences in opinion.
"China has shown some understanding of Japan's principles, but I do not feel we have been able to get over the remaining problems," he said.
Mr Fukuda also reiterated Japan's opposition to Taiwanese independence and voiced his opposition to Taiwan's plans to hold a referendum on UN membership.
Mr Fukuda's trip is the first by a Japanese prime minister since October last year, when his predecessor Shinzo Abe broke a freeze in relations by travelling to Beijing within days of taking office.
China refused high-level contact with Japan during the 2001-2006 premiership of Junichiro Koizumi, after he started making annual visits to the Yasukuni Shrine - a place the Chinese believe glorifies past militarism.
Relations between the two countries began to improve after Mr Koizumi stepped down.
Mr Fukuda has said he will not visit the controversial shrine while he is prime minister and has called for Japan to be humble about its past.
The BBC's Quentin Somerville in Shanghai says the Chinese government has in the past stoked widespread anti-Japanese feeling.
However, no senior figures from Beijing attended the recent commemoration of the 70th anniversary of the Nanjing massacre, a sign he says that perhaps the two countries might be ready to move on.