BEIJING - China, whose disputes with Japan predate World War Two, hopes Premier Wen Jiabao's upcoming visit will be a success in narrowing differences, a Foreign Ministry spokesman said on Thursday.

Wen is expected to visit Japan in the middle of next month, the first visit by a Chinese prime minister in seven years, following a ground-breaking trip to China by Japanese Prime Minister Shinzo Abe last October.

"Premier Wen Jiabao's visit to Japan will be an extremely important one," Foreign Ministry spokesman Liu Jianchao told a news conference.

"We are doing our best to make Premier Wen Jiabao's visit to Japan a success."

A delegation of senior Chinese legislators left Beijing on Thursday for Tokyo on a visit to prepare the way for Wen's visit, the official Xinhua news agency said.

Relations between China and Japan were strained under former Japanese Prime Minister Junichiro Koizumi, who regularly visited Tokyo's Yasukuni Shrine for the war dead that China considers a symbol of Japan's militarism from World War Two.

While Abe has managed to mend fences with his strategy of refraining comment on the Yasukuni issue, his recent remarks about wartime brothels run by the Japanese military has touched nerves in Beijing.

Abe has set off outrage overseas by saying that there was no proof that Japan's government or army had forced women, mostly Asian, to serve Japanese soldiers in the brothels during World War Two.

Liu said on Tuesday that Wen's visit would be shortened as a result.

"China-Japan relations are developing in a good direction," Liu said.

Japanese and Chinese historians agreed on Tuesday to take up some of the thorniest disputes in joint studies of their history, including the Nanjing Massacre and the Yasukuni shrine.

This year marks the 70th anniversary of the Nanjing Massacre and the Marco Polo Bridge incident that led to full-scale war between Japan and China.

Some Japanese historians say the 1937 massacre in Nanjing has been exaggerated, but China says the barbarity of the event is a fact and puts the death toll at 300,000. An Allied tribunal after World War Two estimated that around 142,000 were killed.