'The range of purchases throw a light on India's threat perception as also its perceived role of being a stabilising influence in the region,' says Brigadier S K Chatterji (retd).
Modi, in an op-ed published in the Wall Street Journal, wrote that the US and India are forging a deeper and stronger partnership that extends far beyond the Beltway and the Raisina Hill.
The greatest challenge before India is how to strike a fine balance of its relationship between its neighbour and strategic rival China, and the US.
There are some larger policy issues related to the submarine as a platform and the modernisation programme of the navy that merit brief recall and review, says C Uday Bhaskar
Japanese Prime Minister Shinzo Abe's $12-billion loan at an incredibly low interest rate may have trumped China's aim to enter the enormous Indian Railways market, notes A K Bhattacharya.
'Prime Minister Modi has initiated a host of reforms in the right direction, and I would like to see that continuing.'
Prime Minister Narendra Modi on Tuesday termed his Japan trip as "very successful" and hoped that India's infrastructure will improve and the country will become clean with the help of $35 billion promised by Japan over five years, the highest ever amount ever.
The visit of Park Geun-Hye to India, though a symbolic one, will certainly give a further impetus to the strategic partnership between the two countries says Rup Narayan Das.
'He is seeking to harness the power of Indian Diasporas to national (support for India in global capitals) and political (enhance the Bharatiya Janata Party's support base) ends.'
In recent years India-Japan relations have acquired rich economic content and strategic intents. Although the bilateral trade at $18 billion between the two countries is not very impressive and leaves much to be desired, the economic engagement between the two countries is both qualitatively and quantitatively noteworthy. India-Japan defence cooperation, however, has generated a lot interest among the strategic community in the context of rise of China. There has been a lot of speculation about India-Japan strategic partnership to hedge China, says Rup Narayan Das.
In a few years from now, India will be looking at an entirely different type of military adversary across the borders, in our waters, in the air, in space and in our communication networks, says Nitin Pai.
'The regional context and the personal ties between Modi and Japanese Prime Minister Shinzo Abe to a large extent contributed to this dawn of a new era in bilateral relations,' says Srikanth Kondapalli.
'The military aim in a future conflict, if it can't be avoided, should be to cause maximum damage to the adversary's war waging capability and capture limited amount of territory as a bargaining counter,' says Brigadier Gurmeet Kanwal (retd).
In the light of India's increasingly 'darkening' threat environment and the convergence of strategic interests between China and Pakistan, the IAF's declining combat capabilities are a cause for concern, says Brigadier Gurmeet Kanwal (retd).
'India-US relations seem to have soured when the US expected India to not only balance China in the Asia-Pacific, but also make concessions to Pakistan as a price for US technological help,' says Colonel Anil A Athale (retd).
Both India and China have demonstrated levels of maturity in diffusing tensions and ensuring that the border remains by and large incident free, says Seema Mustafa
I still believe that it is a good thing that think tanks are mushrooming in Delhi. They provide a platform for discussion, even if they shed more heat than light. With Parliament almost incapable of serious debate, informed discussion and civilised discourse, where does this nation get its intellectual churn, asks Mohan Guruswamy.
India's unusual tough stand on the arrest of its diplomat Devyani Khobragade has forced the United States to initiate an "inter-agency review" to look into the lapses that happened in the high-profile case that triggered an uproar in India and strained bilateral ties.
Excerpts from Prime Minister Narendra Modi's speech at the Combined Commanders Conference on board the INS Vikramaditya at sea, off the coast of Kochi.
Being a pragmatist Modi is not likely to give preference to China over Japan. Both security and economic aspects are likely to shape Modi's decision in terms of engaging the two biggest economies of Asia, says Sana Hashmi.
The major driver of Mod's foreign policy can be gauged from his economic priorities such as creating employment opportunities for the youth bulge. Related to this is emphasis on manufacturing, and infrastructure development, which in turn raises the issue of FDI. He has already articulated his views on all these issues, says Rup Narayan Das.
Amberish Kathewad Diwanji tweaks the prime minister's Red Fort speech.
The prime minister's outreach to Japan is a recognition of the civilisational potential that the two nations hold and can wield in evolving an era of 'Asianism' in global politics, says Anirban Ganguly.
From early indications, the Modi government's foreign policy seems to be pragmatic and reciprocal, says K G Suresh.
'The Modi government's pusillanimity vis-a-vis Pakistan makes almost certain that India will, in the coming weeks and months, be confronted with cross border terrorist actions of increasing intensity,' warns Satish Chandra, former deputy national security adviser.
The India that needs strategic alliances, defence cooperation and engaging meaningfully with neighbouring countries is quietly moving ahead with confidence, says Tarun Vijay
In his penultimate State of the Union address, Barack Obama said that the economy is improving.
President Pranab Mukherjee on Monday addressed the first joint sitting of Parliament as mandatorily required under the Constitution after the general elections. The address is the political, economic and foreign policy road map of the Narendra Modi government and covers virtually all crucial areas.