By Manjeet Pardesi and Robert Ayson, both from the School of History, Philosophy, Political Science and International Relations at Victoria University of Wellington.

A few days before Indian Prime Minister Narendra Modi's trip to Japan last week, he is believed to have personally extended his visit into five days to signal the importance that India attaches to its emerging relationship with Japan. In turn, Japanese Prime Minister Shinzo Abe broke with protocol and received Modi in Kyoto as opposed to Tokyo. And unlike a firm handshake that is the generally the norm with Japanese leaders (including in meetings with the US President), Abe greeted Modi with a bear hug.

However, not everything that was promised from the big trip eventuated.

The much anticipated upgrading of the India-Japan defence and foreign affairs 2+2 dialogue to ministerial level was not forthcoming. That's a fairly big deal because this would have been a first for India with any country. But in no less than 39 paragraphs, the Tokyo Declaration for India-Japan Special Strategic and Global Partnership which resulted from the Abe-Modi summit confirms that both countries are committed to a deep and comprehensive relationship, and to letting others know about it.

Numerically, at least, the big story was Tokyo's intention to find nearly US$35 billion in investment for India over the next five years. And there are words in the Declaration about the enhancement of the defence and foreign affairs links. There may also be an upgrade of the three way 'official level trilateral dialogue' with the US to a 'dialogue among their Foreign Ministers'.

But it is the strong sense of Indian and Japanese support for their respective strategic roles that really should catch the eye.

In the context of Abe's determination that Japan be a more active defence player, Mr Modi is now on record as having 'supported Japan's initiative to contribute to peace and stability of the region and of the world.' And then there is Mr Abe's appreciation that his guest selected 'Japan as his first destination for a bilateral visit outside India's immediate neighbourhood.'

The choice of Japan to inaugurate a new era in India's 'Look East' policy should be no big surprise. The not-so hidden subtext behind this emerging bonhomie is of course the dramatic rise of China, which isn't mentioned in the Declaration, but doesn't have to be. In 1978 when China launched its spectacular economic reforms under Deng Xiaoping, Japan's economy was more than 12 times as large as China's. By 2013, according to the World Bank China's economy has eclipsed Japan's and is nearly four times as large as India's. According to one recent estimate, by 2030 the combined economies of Japan and India will be only around 60% of China's.

As China converts its material power into greater regional influence, the common interests between Japan and India in preventing Beijing from holding sway over the region are becoming more pronounced. Both have long-standing rivalries with China: in the case of Japan over history and disputed islands in the East China Sea, and in the case of India over the world's longest unmarked land border and the Tibet issue. Beijing will no doubt also have noticed the commitment of Abe and Modi to 'maritime security, freedom of navigation and overflight…and peaceful settlement of disputes in accordance with international law.'

When coupled with the fact that there is little or no geopolitical baggage between Japan and India, the strategic logic guiding this partnership is compelling. The building blocks of this cooperation are also becoming more evident. India and Japan are keen to upgrade their maritime partnership, and Abe has even referred to the Indo-Japanese friendship as the 'confluence' of the Pacific and Indian Oceans. Earlier this year the bilateral annual Malabar naval exercise between India and the US became a trilateral affair with the inclusion of Japan. Tokyo would like this to be a regular feature of the India relationship, and it got a mention in the Declaration. India may also deem it important because its own 2007 Military Maritime Strategy calls for collaboration 'with friendly nations to build deterrence' even in the absence of formal alliances.

Modi's visit also promoted a high-end defence technology deal with Japan which includes the sale of US-2 amphibious seaplanes to India. This would mark a significant departure from Japan's self-imposed restrictions on the export of defence equipment. And in coming years,  the two countries may sign a civil nuclear deal analogous to the 2008 US-India civil nuclear agreement.

This does not portend a full alliance between these two Asian democracies against a rising China, even as this relationship has Washington's tacit backing. Japan is largely a naval power and is unlikely to be of much direct assistance in the event of Sino-Indian land border conflict. Similarly, while India is slowly transforming its maritime military reach, its ability to project power to the east of the Malacca Strait remains limited. New Delhi is unlikely to play a military role in the event of Sino-Japanese hostilities in the East China Sea and would baulk at the idea of an overt military alliance aimed at China.

But a rapidly developing Indo-Japanese relationship has the potential to divide China's attention between its land and maritime frontiers. In turn China may find more reason to boost its naval power in East Asia and its already strong links with India's subcontinental rival, Pakistan. The sum total of these developments shows that the Modi-Abe concord is a leading part of Asia's big power strategic contest.