This changed on February 24, 1962, when Tezpur-based XXXIII Corps, commanded by the respected Lt Gen Umrao Singh, ordered nine new border posts, included one between Tawang and Bhutan, at the tri-junction of Tibet, Bhutan and India. This post became famous as Dhola. Captain Mahabir Prasad of 1 Sikh established
Dhola Post on June 4, 1962, on what Henderson Brooks reveals was China's side of the McMahon Line.
The HBR blogpost says in August 1962, XXXIII Corps admitted to Eastern Command that its post was wrongly sited but not that it was on Chinese territory. Aware of the consequences, XXXIII Corps suggested that the army play innocent. It wrote, "…to avoid alarm and queries from all concerned, it is proposed to continue using the present grid reference."
Henderson Brookes is frank in his assessment: "This, in effect, meant that the post was actually north of the McMahon Line."
The consequences were not long in coming. On September 8, Dhola Post was surrounded by some 600 Chinese soldiers. Instead of wriggling out from this uncomfortable position, the army chose an aggressive response. The HBR blogpost recounts that, on September 12, four days after Dhola was surrounded, the Eastern Command chief, Lt Gen L P Sen, told Lt Gen Umrao Singh, and GOC 4 Division, Maj Gen Niranjan Prasad that the "Government would not accept any intrusion of the Chinese into our territory. If they come in, they must be thrown out by force."