The Japanese and Indian prime ministers have expressed their commitment to boost strategic and political ties. The Japanese leader visited New Delhi as the friendship between the two countries gains momentum to counter China's growing assertiveness in the region.
Japanese Prime Minister Shinzo Abe watched a display of India's military strength and cultural diversity at Republic Day celebrations in the Indian capital Sunday. He is the first Japanese leader to be the chief guest at the annual ceremony, to which New Delhi traditionally invites countries it is cultivating.
A day earlier, the two countries pledged to strengthen ties after the Japanese prime minister held talks with Indian leaders.
Abe said relations between the two countries have the "greatest potential of any bilateral relationship in the world."
Abe also said the two countries have agreed to step up cooperation in the area of maritime security through active dialogue and visits, adding that he expects there will be a further deepening of cooperation in politics and security.
India and Japan have been holding joint naval exercises since 2012.
The commitment on both sides to closer strategic ties comes as Japan and China dispute ownership of islands in the East China Sea, and as concerns increase that Beijing wants to control vital shipping lanes.
In an interview with an Indian newspaper, Abe said the security environment of the Asia Pacific region is becoming "ever more severe."
New Delhi, which has a long-running border dispute with China, is also wary of Beijing and its growing influence in the Indian Ocean region.
A strategic affairs analyst at New Delhi's Center for Policy Research, Bharat Karnad, says the convergence between India and Japan is driven by their mutual need to counter China.
"One, of course, is the bellicosity of the Chinese, the identification zone that they have declared in the East Sea and of course in the South China Sea and so on and India’s apprehensions as well on the Himalayan front, they are nibbling away at the border," Karnad said. "That is the common kind of concern, and the need therefore for an organic security set up in Asia, meaning like-minded countries trying to get together to see if they can’t begin in some ways to cooperate and collaborate in limiting China's strategic options, military options."
The strategic partnership is being built on a bed of greater economic cooperation, and analyst Karnad says Japan is willing to "put its purse where its mouth is."
The Japanese prime minister announced a $2 billion loan for expansion of the Delhi Metro, and promised more investment in other infrastructure projects, a critical need for India.
Both countries held talks on the sale and co-production of a sophisticated Japanese search and rescue sea plane to India. They also said that negotiations to conclude an agreement on civil nuclear energy had gained momentum. This will pave the way for Tokyo to invest in India's nuclear power sector.
After meeting Abe, Indian Prime Minister Manmohan Singh said Japan was at the heart of India's Look East policy and a key economic ally.