Indian Prime Minister Narendra Modi arrived in Japan yesterday for a three-day visit in a quest to deepen economic ties while reaffirming close political and security ties with the East Asian nation.

"India and Japan see each other through a prism of... democratic values, and commitment to an open, inclusive and rules-based global order," said Mr Modi, who during his visit will ride on the bullet train with his Japanese counterpart, Mr Shinzo Abe.

The two leaders will meet today for talks amid expectations that the two sides will sign a civilian nuclear deal. The deal, in the works for more than six years, will allow Japan to export nuclear technology to India, which is trying to boost its share of electricity run from nuclear sources.

Japanese media has been reporting that the deal is likely to be signed during Mr Modi's visit. If this happens, it would be the first time Japan - which faces sensitivities on nuclear cooperation due to its history - enters into a nuclear deal with a country that has not signed the Nuclear Non-Proliferation Treaty.

India-Japan ties have been progressing smoothly, with closer cooperation seen as an advantage for both countries as both are equally worried about growing Chinese activity in the region. India has a festering border row with China and is uneasy about growing ties between China and Pakistan. Japan has its own maritime territorial dispute with China.

With an eye on China and to deepen military ties, India last year even invited Japan to be a permanent part of a bilateral naval exercise with the United States.

Some analysts believe there would be a strong reaffirmation on freedom of navigation of the seas during the visit.

"On the strategic side, there is going to be an even stronger messaging. For instance, our language about South China Sea ruling and the need to abide by international law, freedom of seas is all going to be fairly strong, as we did on the India-Vietnam joint statement," said Dr Rajeshwari Pillai Rajagopalan, senior fellow at the Observer Research Foundation.

Still, pushing trade between the two countries is expected to be tougher, with Japanese businesses often complaining about matters such as poor infrastructure, including patchy electricity supply in many parts of India.

Trade between India and Japan stood at US$14.5 billion (S$20.4 billion) for the 12 months ended March 31 this year, a dip of over 6 per cent from the preceding year.

"The word going around is that India hasn't changed much. They (Japanese businesses) are looking more at Vietnam and Indonesia," said Professor Prem Motwani, a Japan expert at Jawaharlal Nehru University.

"At the political level, both heads of state are on the same page but that doesn't really translate at the grassroots level."