Tokyo: Prime Minister Manmohan Singh arrived here on a rain-splattered on Sunday evening for a three-day visit to further India's strategic interests with Japan straddling the twin fronts of economy and diplomacy.

Manmohan Singh, accompanied by his wife Gursharan Kaur, was welcomed at the Haneda International Airport by Japanese Vice Minister for Foreign Affairs Ikuo Yamahana. In Tokyo for the India-Japan annual summit, Manmohan Singh will discuss with his counterpart Naoto Kan the gamut of bilateral, regional and global issues.

India is expected to announce the conclusion of negotiations on the Comprehensive Economic Partnership Agreement (CEPA) with Japan. However, the actual signing of the agreement will have to wait for the internal processes that Japan has to go through.

Discussions on the civil nuclear deal are also still on. With nuclear being a particularly sensitive subject in Japan, the deal will take some more time to fructify though there was political resolve in both countries to take these discussions forward, informed sources said.

There is also an economic impulse driving the deal that would be achieved in a gradual way rather dramatically, the sources added. India is also clear that the basic template of the deal should be the same as others. "For us, the value is that we're both on the same table," said a source.

The strategic relationship, it is believed, has long term significance and affects the futures of both countries.

"We are now cooperating in areas we only with close friends," said a source, citing not just the civil nuclear deal but also the fact that "we have excellent conversations" on political issues such as Afghanistan.

Defence cooperation has really grown as has the scope of what Japan has done for the Indian economy.

The two governments, it is learnt, have prepared a project development fund for the Delhi-Mumbai industrial corridor. The idea, the sources said, is that initially governments come in and later private investment is invited, particularly from Japanese companies.

"It's an old relationship," is how a source put it, with a certain comfort level that goes back to the times of Netaji Subhas Chandra Bose when he and the Indian National Army got support from Japan during the heydays of the freedom struggle.

The Japanese involvement in major infrastructure development projects in India, like the dedicated freight corridor and the industral corridor, will also be discussed by the two prime ministers.

"The tradition of annual summit with Japan has resulted in a strong, vibrant and multi-dimensional relationship between India and Japan.

"Strengthening of the India-Japan strategic and global partnership enjoys the fullest support across the political spectrum in both our countries and is a factor of peace, prosperity and stability in Asia and the world," the prime minister said in New Delhi before take-off.

Describing Japan as a major economic partner of India, Manmohan Singh said India had embarked upon mega infrastructure projects with Japanese assistance with a view to transform the Indian economy.

"Our trade relationship is set to enter a new phase," he said. The Indian leader will address Japanese business leaders and meet a cross section of Japanese political leaders.

From Japan, the prime minister will travel to Malaysia and then Vietnam before returning home on October 30.