When people in China or India ask me about the difference between their two countries, I tend to open with a simplistic joke: "Roads," I say, referring to the yawning gap between China's endless highways and India's debilitating infrastructure deficit.
But as Chinese President Xi Jinping prepares for a much-hyped bilateral visit to India next week – his first since Indians elected Prime Minister Narendra Modi with the strongest electoral mandate in a quarter century – it is worth dwelling more deeply on the differences between Asia's two giants, and whether now is a time when they can overcome distrust, find similarities and help reshape regional dynamics.
The two countries, though, do not make easy allies – and not just because they are separated by some of the most fearsome geography on Earth.
India is an exuberant democracy with a vibrant free press in a shambolic neighbourhood. China, of course, is an autocracy that, despite having raised hundreds of millions out of poverty in recent decades, has granted few freedoms – and still locks away dissenters.
Mr. Modi used his first bilateral trip outside of the subcontinent to travel to Japan, where like-minded Prime Minister Shinzo Abe gave him a bear hug and promised billions in investment; Mr. Modi, in turn, used his trip to warn the world of certain "expansionist" countries in East Asia – an obvious reference to China.
China, on the other hand, has long enjoyed close ties with Pakistan, India's nuclear nemesis next door, where a Chinese state-owned firm now operates the strategic deep-water port at Gwadar.
The two Asian giants have diverged radically in terms of economic development over the past few decades, something which shapes their needs today: China craves resources and a more sustainable pace of growth, while India desperately needs to revive growth by building basic infrastructure and growing a manufacturing base to employ its youth.
China and India also generally enjoy different relations with their smaller neighbours in Asia: Mr. Modi is trying gently to boost India's trade with Nepal, Bhutan and Sri Lanka, for example, while China continues to act aggressively with Vietnam and the Philippines over maritime boundaries in the South China Sea.
There is also simmering tension over a border dispute that prompted an outright war in 1962 – which China won – as well as India's support for the Dalai Lama and Tibetan exiles in Dharamsala. I could go on.
Then there are the powerful similarities.
Both are huge developing countries with proud, historic cultures. They both have an uneasy relationship with the United States – which for years banned Mr. Modi from visiting because of his perceived role in the anti-Muslim riots of 2002 in his home state of Gujarat.
Mr. Modi – a right-leaning, business-friendly and pseudo-autocratic ruler himself – is a big fan of China's economic accomplishments: As chief minister, he visited China four times to court investment to Gujarat, and said in 2011 that "the two great countries will make Asia the centre stage of the global economy." China is now India's largest trading partner (though admittedly, China is a lot of countries' largest trading partner).
Both nations also dislike the post-1945 world order of international institutions dominated by Western powers, as well as some priorities – such as climate change or, in China's particular case, human rights – that might handcuff their ability to order their affairs as they please.
And there are needs, too. India craves Chinese investment. And China wants India's participation and support as it tries to tilt the global balance of power to the east, and particularly to regional forums it dominates (such as the Shanghai Co-operation Organization) or looms large over (such as the Association of Southeast Asian Nations).
As Mr. Modi seeks to reshape India's economy and build out infrastructure, he has a powerful potential ally in Mr. Xi. The Chinese president, who is consolidating power at home and can wield investment and Chinese industrial heft abroad, is expected to spend heavily on Indian industrial parks, including one in Gujarat. The Chinese president may also get involved in India's underutilized rail system, which Indian industrialists desperately hope to use for shipping.
But beyond trade and investment deals and bold declarations, the odds are stacked against any long-term geopolitical realignment, suggests Joseph Caron, a former Canadian ambassador to China and Japan, as well as ex-high commissioner to India.
"They pretty well see eye-to-eye on environmental issues" and on the World Trade Organization, Mr. Caron said from Vancouver, where he now serves on corporate boards. He note that Mr. Modi, much to China's liking, recently refused to sign the WTO's Doha agreement on reform of the international trading system. But, he added, "there are a lot of moving parts and not that many reasons for strategic collaboration, except in narrow matters."
Mr. Caron, who retired from the foreign service in 2010, said that he arrived in India after his time in China and "finally realized how high the Himalayas are." Very little united the two countries or cultures, he said, and even Buddhism, which made its way to China from India along the Silk Road, is an ancient, almost useless bond. "Harking back to that is entirely artificial," he says, given Buddhism's long decline as a cultural force in India.
There is, he said, a vein of mistrust in elite Indian thinking about the United States. China knows it can seize on that and marshal its great resources to underwrite its diplomatic overtures.
That's not to say that co-operation between China and India automatically creates some anti-Western cabal: Even if Mr. Modi is unlikely to deploy military might to help out smaller Southeast Asian countries in China's backyard, India could act to stabilize the region, work as a democratic counterweight to China and perhaps even help shape China's inevitable rise.
But even if there is co-operation, there should still be skepticism.
"You can always find reasons, just like the U.S. and Iran on [the Islamic State] – there is sometimes a coincidence of common interests. [And] that may indeed multiply over time," Mr. Caron said. But, "any comment or declaration by China and India, that they see 'eye to eye on X,' you've got to really look very closely. … Because their interests are very, very divergent."