How did Thag La come to be treated as Indian territory when it was shown North of the McMahon Line on the Survey of India maps? The answer is to be found in the Simla Convention of 1914. At this Convention, Sir Henry McMahon had generally taken the Himalayan watershed as the frontier. In fact, one of the objectives of the Indian Government at this convention was to secure a strategic watershed boundary between the two countries.

Where the boundary terminated in the West, ‘there was no watershed to be followed, and McMahon drew his line along what his maps showed as outstanding ridge features’.2 However, after Independence when the Indian authorities began to take a closer look at the country’s Northern borders, it was found that on transposing the McMahon Line to the ground from its map coordinates, the line would not run along the highest ridge in the area. The Thag La Ridge, lying four to five kilometres North of the map-marked McMahon Line, was the highest feature and India decided to treat the crest of this ridge as the boundary.

Che Dong was no prominent landmark, or a feature of tactical importance. It was merely a cluster of herders’ huts built by Monpa tribesmen of the region. The huts lay a short distance from the spot where the boundaries of India, Bhutan and Tibet meet.

Thag La is higher than Tsangdhar and runs almost parallel to it. Thus, the Che Dong Post was overlooked by Thag La as also the Tsangdhar range itself. Sited thus, it served no purpose. In case the Army wanted to set up a post in the region, it should have been sited either upon Thag La or atop Tsangdhar.

The Assam Rifles were responsible for setting up border posts. However, as the latter were under the Army’s operational control, it helped in their establishment. While this particular post was being set up, the officer entrusted with the task was questioned over the radio by the General Officer Commanding 4 Infantry Division, Major General Niranjan Prasad, as to why a site shown North of the McMahon Line on the map was selected. In reply he was told that according to the Intelligence Bureau representative with the party, even the Thag La Ridge was Indian territory. In most contemporary records, the post is incorrectly mentioned as the Dhola Post. The Dhola feature, in fact, lay a few kilometres South of the McMahon Line but the man on the spot somehow gave this name to the post at Che Dong and it stuck.

As it was, Thag La was important for the Chinese too. On its Northern slopes was Le, a large Tibetan village, which was the obvious site for a Chinese forward base for any operations against India in this sector. Besides, there had been trouble over the ridge earlier.

In August 1959, the Assam Rifles set up a check post at Khinzemane, on the South-Eastern tip of the Thag La Ridge where the Namka Chu joins the Nyamjang Chu, a river that flows from Tibet into NEFA. The Chinese reacted sharply. About 200 of them appeared on the scene and pushed the Assam Rifles’ men to the bridge on the Nyamjang Chu at Drokung Samba, a few kilometres to the South which they claimed was the boundary according to the McMahon Line. Thereafter, the Chinese withdrew. A couple of days later, the Assam Rifles returned to Khinzemane. The Chinese again tried to push them out but this time the Assam Rifles made it clear that they would resist.

To reach the Assam Rifles’ post at Che Dong, one had to leave the Shakti-Khinzemane route about 5 kilometres short of the point where the Namka Chu meets the Nyamjang Chu, go West to Lumpu (3,048 metres), whence a path led North across Hathung La (4,396 metres) to Che Dong. The last leg of this route ran along the North bank of the Namka Chu, right under the Chinese positions on Thag La. Indian troops had, therefore, to use an alternative route later on.

For the Chinese, access to the Namka Chu Valley was comparatively easy. From Thag La, their forward base at Le was only a three-hour march away. During their offensive, they extended their motor road from Tsona Dzong to Towang over Bum La.

Lack of intelligence about Chinese intentions and their preparations was a major deficiency on the Indian side. In the Indian Army’s plans, it was assumed that the Chinese would not be able to deploy more than a regiment (brigade) against Kameng.

On 10 September, Niranjan Prasad arrived at Towang. He had with him a radio signal from Eastern Command, The message ordered the immediate move of 9 Punjab to the Che Dong area; the rest of the brigade was to get ready to join the battalion within 48 hours. The message said that all troops should go prepared for battle and, if possible, an attempt was to be made to encircle the Chinese investing Dhola Post.

The operation was given the code name ‘Leghorn’. Besides bringing him these orders, Prasad told Dalvi that his brigade was to be reinforced. For this purpose, 2 Rajput had been placed under him and ordered to move up straightaway. When moves were ordered to build up 7 Brigade, no thought was given to the problems of movement in the mountains, or to the logistic support of the troops inducted.

The first man to stand up and argue was Lieutenant General Umrao Singh. He pointed out that the troops were on restricted rations as bad weather had been interfering with air-drops and that they had no reserves. They would have to operate at altitudes up to 5,250 metres; winter was approaching and they would need heavy clothing and tents. However, Umrao Singh’s arguments and suggestions fell on deaf ears; Sen merely reaffirmed his earlier orders.

Meanwhile, 9 Punjab was on its way to the Namka Chu under its commanding officer, Lieutenant Colonel R.N. Misra. The battalion had established a base at Lumpu, which had a helipad and a dropping zone.

Mid-September was harvesting time in these parts. No ponies or porters were available and 9 Punjab had to carry everything manpack. The men moved with one blanket, a hundred rounds of ammunition, two grenades, three days’ rations and their share of light machine-gun magazines. The total load per man was 30 to 35 kilograms.

The battalion took the Hathung La route from Lumpu and after a day’s forced march, reached Bridge I late in the evening on 14 September. The next morning, after dropping one company at Bridge I, Misra took the rest of the battalion to Bridge II, where a company of Chinese troops was in position on both sides of the Namka Chu.

On seeing the Punjabis’ column, the Chinese South of the river began to shout in Hindi that the Indians should withdraw from the Kachilang (their name for the Namka Chu) area, as it was Chinese territory. They claimed to be frontier guards and asked why India had moved regular troops.

Misra’s orders were to fire only in self-defence and to sit in front of the Chinese if they refused to vacate Indian territory. He, therefore, left two of his companies about 50 metres South of the Chinese position at Bridge II and led the remaining company to Che Dong, which was reached at 1400 hours.

That night (15 September), 9 Punjab at Bridge II carried out a clever manoeuvre. They crept closer to the bridge. The Chinese started shouting but withdrew to the North bank, leaving two sentries on the South bank.

On 19 September, the 9 Punjab received an intriguing radio signal. It was from Army Headquarters and addressed to everyone in the chain of command down to the battalion. It ordered the battalion to capture, as soon as possible after arrival on the Namka Chu, the Chinese position 900 metres North-East of Che Dong, contain the Chinese South of Thag La and, if possible, establish two posts atop the Thag La Ridge (height over 5,250 metres).

When this order reached 9 Punjab, Dalvi was on an inspection tour of the battalion. He told Misra to take no notice of it, and informed Niranjan Prasad of his action. The latter protested to 33 Corps regarding the propriety of this order being given direct to one of the units under him. Umrao Singh, in his turn, asked Eastern Command to have the order cancelled. 9 Punjab were at this time living on rice and salt; they did not even have sugar for their tea. Perhaps this did not interest those who issued the order.

The close proximity in which Indian and Chinese troops were placed along the river was bound to lead to trouble sooner or later. The night of 20 September saw the first outbreak of firing. Around 2230 hours, a Chinese sentry on Bridge II lobbed a grenade into one of the Punjabis’ bunkers. Thereupon the latter opened fire, killing one Chinese soldier on the South bank and another across the bridge. Intermittent firing continued throughout the night. The Punjabis suffered four casualties.

By the time the Indian battalion reached the point of conflict, Chinese units controlled both banks of the Namka Chu River. On 20 September, Chinese troops threw grenades at Indian troops and a firefight developed, triggering a long series of skirmishes for the rest of September.

On 10 October, an Indian Rajput patrol of 50 troops to Yumtso La were met by an emplaced Chinese position of some 1,000 soldiers. Indian troops were in no position for battle, as Yumtso La was 16,000 feet (4,900 m) above sea level and Kaul did not plan on having artillery support for the troops. The Chinese troops opened fire on the Indians under their belief that they were north of the McMahon Line. The Indians were surrounded by Chinese positions which used mortar fire. They managed to hold off the first Chinese assault, inflicting heavy casualties.

At this point, the Indian troops were in a position to push the Chinese back with mortar and machine gun fire. Brigadier Dalvi opted not to fire, as it would mean decimating the Rajput who were still in the area of the Chinese regrouping. They helplessly watched the Chinese ready themselves for a second assault. In the second Chinese assault, the Indians began their retreat, realising the situation was hopeless. The Indian patrol suffered 25 casualties, and the Chinese 33.