New Delhi: Prime Minister Manmohan Singh's visit to Japan next week is likely to test his diplomatic skills as he seeks to persuade Tokyo, a key member of the Nuclear Suppliers Group (NSG) and known for its strong views on non-proliferation, to back the India-US civil nuclear deal at the nuclear forum.

Although economic issues will dominate the four-day visit beginning Dec 13 with a view to forging a special relationship between the two Asian countries, it will have substantial strategic and political content as well.

In terms of India's civil nuclear diplomacy, Manmohan Singh's Tokyo visit is astutely timed: it will be the first NSG country the prime minister will visit after a likely approval of the final nuclear bill following a reconciliation conference of the two chambers of the US Congress.

From India's point of view, getting Japan's support, which abides by the three principles of 'no possession, no production and no presence' of nuclear weapons on its soil, in the NSG to change global rules of civil nuclear commerce in New Delhi's favour will be nothing short of a breakthrough.

In an interview to Yomiuri Shimbun, Manmohan Singh has sought Japan's support for civil nuclear cooperation while underlining New Delhi's "impeccable non-proliferation record".

"There is a strong case to be made that the international community must make a distinction between an open, democratic and responsible state like India from others who have pursued clandestine programmes and indulged in proliferation," he said, rejecting any parallel between India and North Korea. 

Official sources told sources that India was in informal talks with NSG countries including Japan to secure their backing for civil nuclear cooperation. 

Former Indian foreign secretary Salman Haidar underlined the problems vis-à-vis Japan.

"It will be difficult to get Japan's support for the nuclear deal," he told IANS, pointing out the special sensitivities over the nuclear issue of Tokyo, the only country to have been attacked by atomic bombs. 

"Japan will, however, not campaign against us. In the NSG they will not play the spoiler. But they won't be too happy either," Haidar stressed.

This, some experts say, appears to be a fair assessment of the ground realities as Japan is an ally of the US and, therefore, in the end will be unlikely to oppose the India-US nuclear deal.

The Indo-US pact seeks to transfer civil nuclear technology to India although the latter is not a signatory to NPT.

Japan is the world's third-largest nuclear power nation in terms of the number of civilian nuclear plants in operation. Japan's 55-odd plants produce nearly 30 per cent of its electricity needs.

Its support for India's quest for nuclear energy is significant because it was one of the few countries that expressed its reservations over the India-US nuclear deal at a meeting of NSG last year.

Japan, which never missed an opportunity to attack India's nuclear tests of 1998 and has vigorously batted for protecting the Nuclear Non-Proliferation Treaty (NPT), is keen to forge a strategic partnership with New Delhi.

Tokyo's backing - if it comes - will create a positive effect on other members of NSG like the Scandinavian nations who too are not happy with making New Delhi an exception from the NPT regime. 

Manmohan Singh's visit to Japan, which enjoys the protection of the US nuclear umbrella, comes when a debate has revived there over developing nuclear weapons in response to the Oct 9 North Korean nuclear test, which Japan Prime Minister Shinzo Abe called a grave threat to Tokyo's security.

Although Japan has decided for now not to go nuclear, observers say the nuclear option cannot be ruled out. Japan has nearly 43 tonnes of plutonium stockpile from its large civil nuclear industry, which could be diverted for developing nuclear bombs.