Even as President Xi Jinping and Prime Minister Modi prepare to discuss a growing economic relationship and a Chinese role in building infrastructure in India, public interest centres on whether the two leaders might make headway in resolving the Sino-Indian boundary dispute.
Beijing and New Delhi agree that the Sino-Indian border - the 4,000-kilometre Line of Actual Control (LAC) - has remained entirely peaceful for 40 years. Yet, even as a series of military confidence building measures (CBMs) have forestalled any shooting, low-grade confrontation continues as both armies patrol territory that they claim, ignoring the other side's claim to the same area.
With an activist Indian media playing up each incident, perceived violations by Chinese army patrols have cast shadows over Premier Li Keqiang's visit to India in 2013, and then President Xi Jinping's visit in 2014.
While the Chinese media has been restrained in comparison, there is equal jingoism on Chinese social media platforms, especially micro-blogging sites like Weibo. Even the Chinese government, for all its untrammelled power, appears unable to buck Chinese nationalist sentiment with any concessions to India.
Yet speculation continues about a possible border settlement. Foreign Minister Sushma Swaraj, visiting Beijing earlier this year, declared, "an out-of-the-box solution may still come on this". Noted China expert, Shyam Saran, says that former Australian prime minister, Kevin Rudd, after discussions in China, revealed in March to interlocutors in New Delhi that Beijing would present a "surprise package" on the border during Mr Modi's visit to China this week.
In fact, this would seem unlikely, given Beijing's core concerns. China's leaders have consistently viewed the Sino-Indian boundary question as directly linked with anti-China unrest in Tibet, a concern that remains unaddressed. Indian analysts are wrong in believing that Beijing's unwillingness to settle the border stems from the wish to keep India off-balance.
Rather than the calculating dragon of Indian apprehensions, China is an insecure country when it comes to Tibet. Given India's proximity to Tibet, its hosting of the Dalai Lama, the Tibetan government-in-exile (called the Central Tibetan Administration, or CTA) and a network of Buddhist monasteries that mirror counterparts in Tibet, India is the only country in the world that can keep the pot bubbling in that restive region of China.
Notwithstanding repeated Indian statements that it recognizes Tibet as Chinese, Beijing clearly worries that settling the border would free up India to make mischief in Tibet.
Noted Chinese specialist on South Asia, Zhang Li, argues that Tibet has gone up in flames each time China has tried to settle relations. Following the Panchsheel Agreement of 1954 came the Tibetan Uprising of 1958-59; and following the "Political Parameters" agreement of 2005 came the uprising in 2008-09.
Explicitly pointing to the connection between Tibet and the border settlement, Li says: "If Tibet is more stable then the Chinese government will be more flexible in discussing the border issue with India. For the Chinese government it is much more important to stabilize Tibet than it is to settle the border issue early as India has expected."
In other words, Beijing would be willing to settle the border only once the Dalai Lama issue is resolved, preferably with him returning to Lhasa under close Chinese supervision and the closing down of the CTA.
Indian policymakers, however, reject outright any possibility of "delivering" the Dalai Lama to China, after having provided him political asylum for 56 years.
Nor is India about to hand over Tawang - a border district in Arunachal Pradesh that Beijing insists must be ceded to it. Populated by vehemently anti-China Buddhist Monpa tribals, New Delhi cannot throw them under the Chinese bus.
Furthermore, Beijing and New Delhi agreed in the "Political Parameters" agreement of 2005 that "settled populations" - code for Tawang - would not be unduly disturbed in a final boundary settlement. Beijing is seeking to back off from this commitment, but that would be unacceptable to New Delhi.
China's insistence on Tawang dates back only to 1983. Before then, China had proposed a clean "east-for-west swap". This involved India ceding to China the 35,000 square kilometres Aksai Chin plateau, adjoining Ladakh, which is called the "western sector". In exchange, Beijing would accept India's ownership of the 90,000 square kilometres Arunachal Pradesh, or the so-called "eastern sector". The 5,000 square kilometres "central sector" would see minor adjustments.
China already occupies the uninhabited Aksai China, while sparsely populated Arunachal Pradesh has long been held by India. Thus the proposed "east-for-west swap" would not require any significant exchange of territory.
In 1993, however, Chinese leader, Deng Xiao-ping hardened Beijing's stance. He declared that India would have to make "significant and meaningful" concessions in the "eastern sector", a game-changing demand that involved, as spelt out by Beijing, the "restitution" of Tawang to China.
The phrase "restitution" is significant. Tawang was administered by Tibet until 1951, when Indian authorities first arrived there and evicted the Tibetan ecclesiastical rulers appointed by the Dalai Lama from Lhasa.
Since then, the Dalai Lama has declared on several occasions that Tawang is a part of India. China, bent on asserting full control over Tibet, does not believe so. With India unwilling to part with Tawang and with China wanting a pacified Tibet as a pre-requisite to a border settlement, Modi and Xi have little space for moving forward on the border issue.
