A group of bipartisan Japanese lawmakers began their trip to Beijing on Sunday, with more delegations from Japan scheduled to visit China later this month.
The delegation members are expected to find remedies to boost communication between the two neighbours at a time when official contacts have hit a record low, observers said.
Masahiro Koumura, visiting vice-president of Japan's ruling Liberal Democratic Party, led the union delegation to Beijing for the three-day visit.
The delegation consists of lawmakers from the ruling coalition and the opposition, including Katsuya Okada, a senior member and former chief of the Democratic Party of Japan.
Former Chinese state counselor Tang Jiaxuan held a meeting on Sunday evening with Koumura, former Japanese foreign minister and now the president of Japan-China Friendship Parliamentarians' Union.
Tang said Beijing "places great priority" on Koumura's friendly visit when the ties are facing huge challenges. Koumura said he hopes the visit may help improve the relationship.
Japan's public broadcaster NHK said Koumura will seek a "breakthrough" for improving the relationship.
Bilateral ties were stalled after the Japanese government unilaterally announced the decision to "nationalise" part of China's Diaoyu islands in September 2012.
Sun Cheng, professor of Japan studies at China University of Political Science and Law, said the grudges between the two countries have expanded from the islands issue to an overall confrontation on a diplomatic level, which is "unlikely to be resolved in a short period of time".
"The ties may not be improved unless the relevant issues are properly addressed and disputes are appropriately managed," Sun said.
The diplomatic climate worsened after Japanese Prime Minister Shinzo Abe made a pilgrimage to Tokyo's Yasukuni Shrine in December, which enshrines 14 Class-A war criminals.
Commenting on Tokyo Governor Yoichi Masuzoe's visit to China on April 24 and Koumura's trip, Foreign Ministry spokesman Qin Gang said on Wednesday that Beijing "welcomes people from all walks of life in Japan, including figures from the ruling and the opposition parties, to play a positive role in improving the China-Japan relationship".
On April 28, Abe told Koumura that the "Japan-China relationship is a great priority" after Koumura briefed the prime minister of his upcoming visit to China. Abe "seems to have an expectation for Koumura's China visit, hoping it will prepare a climate for a leaders summit", Japan's Tokyo Broadcasting System television said.
Several groups of Japanese lawmakers have expressed their intentions to visit China in May, Japan's Asahi Television commented.
Takeshi Noda, chairman of the LDP's Research Commission on the Tax System and a member of the House of Representatives, will lead another delegation to China from Wednesday to Friday, according to Japan's Sankei Shimbun newspaper.
In a separate development, Japan marked the 67th anniversary of its postwar Constitution on Saturday with growing debate over whether to revise the war-renouncing charter, The Associated Press said.
"Now Abe is proposing that the government reinterpret the Constitution to give the military more prominence without having to win public approval for the revisions", while hundreds of people gathered at a Tokyo rally commemorating Constitution Day, a national holiday, AP said.