Shinzo Abe is president of the Liberal Democratic Party and was elected prime minister of Japan in December 2012. He also served as prime minister in 2006 after being elected by a special session of Japan’s National Diet, but resigned after less than a year.
Hopes high in Japan for Masahiko Komura’s mission to Beijing
Masahiko Komura's visit to China will be judged by who the LDP No 2 meets and whether he can pave way for more cordial ties
Julian Ryall in Tokyo
When Masahiko Komura arrives in Beijing on Sunday, the vice-president of Japan's Liberal Democratic Party will be bearing a personal message from Prime Minister Shinzo Abe as well as his government's hopes that bilateral ties might be improved.
Tokyo is watching very carefully to gauge the warmth of the greeting that he and the other eight members of the Japan-China Friendship Parliamentarians' Union receive and the seniority of the representatives of the Chinese government they are able to meet.
"Komura is known to be very pro-Chinese and has strong relations with many people in key political and business positions in Beijing," Go Ito, a professor of international relations at Tokyo's Meiji University, said.
"This visit is symbolic. The Chinese are aware of that, and it will be interesting to see the rank of the person that Komura is able to meet during his stay."
Komura has been sent to Beijing with the aim of paving the way for better diplomatic relations and, ultimately, a resumption of top-level talks between the two governments. Japanese media reported that diplomatic sources had said Abe told Komura: "I want you to convey Japan's will to restore [bilateral relations] to a mutually beneficial relationship based on common strategic interests."
Abe has not been able to meet his Chinese counterpart since he was elected in December 2012, with the Sino-Japanese relationship sinking to new lows in the last couple of years.
The row over the sovereignty of the Senkaku Islands, which China claims as the Diaoyu archipelago, has polarised opinion in both countries.
That mutual distrust has been worsened by different interpretations of the two nations' shared history, including the issues of "comfort women" during the second world war and the Nanking Massacre.
The Japanese delegation also includes Kazuo Kitagawa, the deputy leader of New Komeito, the LDP's ally in government, and Katsuya Okada, the former head of the opposition Democratic Party of Japan.
Komura is considered the Japanese politician most likely to be able to make the breakthrough to the upper echelons of the Chinese leadership, as he met Xi Jinping in 2011, when he was vice-president but already tipped for the nation's top post. Komura's speaking with Xi - even if only briefly - would be considered a positive sign in Tokyo.
Yoichi Masuzoe, the governor of Tokyo, paid a three-day visit to China last week and was able to meet Wang Yang , a vice-premier and one of 25 members of the Communist Party's Politburo. Should Komura only warrant a meeting with an official of Wang's rank, then Tokyo is likely to consider the attempt to offer an olive branch a failure.
"My understanding is that Xi and the Chinese government are probably just waiting for the Abe administration to end and hoping that it will not be too long," said Ito. "I'm sure they would prefer to see Komura - or someone like him - in power here, although he is too old now, of course.
"For now, Komura may have limited influence on either side, but he is a good conduit, and I think he will be happy to play that role," Ito added.
People from all walks of life in Japan are welcome to make positive moves to improve China-Japan relations, a Chinese Foreign Ministry spokesman said on Wednesday.
Qin Gang was asked at a news briefing about Japanese politicians' visits to China, including those of Masuzoe and Komura. "China's stance on developing China-Japan relations is consistent and clear," Qin said, noting that China urges Japan to push forward bilateral relations in the spirit of taking history as a mirror to guide the future.
Additional reporting by Xinhua