India and China came close to the edge in June. They may be heading over it now.

It started this summer when the world's two most populous countries clashed at their border in the Himalayas. In the Galwan Valley, a brutal melee broke out when Chinese soldiers refused to remove tents from territory claimed by India. There were 20 Indian soldiers killed; China has yet to disclose its casualties.

Since then, thousands of troops have poured into Ladakh in India and the neighbouring Tibet Autonomous RegionAutonomous means self-governing. Tibet has been at times both a protectorate of the Chinese empire and a mostly independent nation (between 1912 and 1951). In 1959 there was an uprising aiming for independence. Instead, it is now an autonomous region. in China. Each country argues that the other has violated the Line of Actual Control.

This is a loosely defined border, left in place after the 1962 Sino-Indian WarThis conflict between India and China was likewise started by border disputes.. The two countries have been at loggerheads ever since - over where one country ends and the other begins. Over the years, several skirmishes have broken out in the disputed Aksai Chin region.

Now, the Indian government has acted against what it calls Chinese "provocations" by moving troops on to the high ground at Pangong lake. One Indian-Tibetan soldier died in a landmine explosion prior to India taking the ground.

Occupying Pangong gives India a strategic advantage over the People's Liberation ArmyChina's army traces its origins back to the 1927 purge of communists by the Nationalist Kuomintang party, but it was only named the PLA after the defeat of the Japanese in World War II in 1945.. China, however, has condemned this as an incursion into their territory.

The lake is also close to the site of the battle of Rezang La, one of the key actions of the 1962 war. There, 120 Indian soldiers fought to their deaths against over a thousand Chinese troops.

The ThermopylaeA famous battle between the ancient Greeks and Persians, where the Spartan king Leonidas, with only 300 men, is fabled to have held back the Persian army numbering in excess of 100,000.-like symbolism of the battlefield is clearly not lost on either country in this time of rising nationalism. Both China and India have lately been pursuing more aggressive regional policies. India revoked the special status of the Kashmir region last year. China, likewise, has weakened the relative independence of Hong Kong.

India's actions in Kashmir may have threatened China's interests in the region, triggering the show of strength at the border. Chinese president Xi Jinping has called for more "fighting spirit" in Chinese diplomacy. It's clearly on display in these clashes with India.

As well as being regional rivals, both countries are also nuclear powers. With over 40% of the world's population between them, a war could be devastating.

Some observers hope that this is mere sabre-rattlingLiterally, making noise with your sword to intimidate your opponent, but it has come to mean making verbal threats or taking actions to achieve the same result.. Against the backdrop of a damaging trade war with the USA, Xi may be trying to show other Asian countries who's boss by picking on the biggest one. At the same time, Indian Prime Minister Narendra Modi would welcome a distraction from the coronavirus crisis.

India has just banned a range of Chinese apps, including the battle royale game, PUBG. For some, that means the fighting is over. For others, it may signal the real conflict to come. One anonymous Indian official told the Washington Post that "India is willing to take blood and lose blood".

War is coming, say some. When neither side is prepared to back down on matters of national pride, conflict is inevitable. Until the border question is resolved, neither country will give an inch. China is more concerned about its rivalry with the USA; it sees India's actions through this lens and is underestimating and provoking India with dangerous consequences.

War is not the answer, say others. It's not even the question. If China's real concern is extending its power globally, it will not push India too far. As the coronavirus recession bites, and Himalayan winter makes fighting difficult, both sides will quietly drop their posturing. China and India have been playing for a domestic audience, and a war between nuclear powers is still unthinkable.

Tibet Autonomous Region - Autonomous means self-governing. Tibet has been at times both a protectorate of the Chinese empire and a mostly independent nation (between 1912 and 1951). In 1959 there was an uprising aiming for independence. Instead, it is now an autonomous region.

Sino-Indian War - This conflict between India and China was likewise started by border disputes.

People's Liberation Army - China's army traces its origins back to the 1927 purge of communists by the Nationalist Kuomintang party, but it was only named the PLA after the defeat of the Japanese in World War II in 1945.

Thermopylae - A famous battle between the ancient Greeks and Persians, where the Spartan king Leonidas, with only 300 men, is fabled to have held back the Persian army numbering in excess of 100,000.

Sabre-rattling - Literally, making noise with your sword to intimidate your opponent, but it has come to mean making verbal threats or taking actions to achieve the same result.