Many of the cargo containers passing through India's busiest port in Mumbai have a small piece of Japan Inc. attached: Devices from NEC Corp. that can be tracked as the containers rumble through the interior of Asia's third-largest economy.

The partnership between NEC and the port illustrates the strengthening relationship between Tokyo and New Delhi. Japan is seeking growth markets, while India craves advanced technology and foreign investment. The leaders of both countries, Shinzo Abe and Narendra Modi, are also working to counter the growing regional influence of China — an important economic partner to both but also historically a rival.

"We have the two largest democratic economies in this region, we respect international rules, openness and transparency — these are basic principles that we share," said Kenko Sone, a former head of global communications for Abe who now serves as minister of economic affairs at Japan's embassy in Delhi.