Prior to Bangladesh Liberation War in 1971, India had no plans for large scale military action in East Pakistan. Since the Sino-Indian War of 1962, the primary objective of the Indian Army Eastern Command was the defence of the Indian northern and eastern borders, defending the "Shiliguri Corridor", and on combating insurgencies raging in Mizoram, Nagaland, Manipur and the Naxalites in West Bengal.
Since 1948, bulk of the Pakistan Armed Forces were stationed in West Pakistan and the strategic role of the forces in East Pakistan was to hold out until Pakistan defeated India in the west. The Pakistan Army Eastern Command had planned to defend Dhaka until the last by ultimately concentrating their forces along the "Dhaka Bowl", the area surrounded by the rivers Jamuna, Padma and Meghna.
Indian Eastern Command deployments 1971 The Indian Army kept parity with Pakistani forces stationed in East Pakistan since 1965, and in 1971 one armoured brigade and one infantry division was deployed in West Bengal. Other Eastern Command units were deployed in Mizoram, Manipur, and Nagaland. Eastern command had 4 administrative units: the Bengal Area corps (the 9th division and other units), the XXXIII corps (3rd armoured brigade, 17th, 27th, 6th and 20th Mountain divisions) guarding the Shiliguri corridor, as well as ensuring security of Sikkim and Bhutan if needed, the 101st Communication Zone (no combat units, an administrative unit which operated in the area between the XXXIII and IV corps), while the IV corps (2nd, 5th, 23rd, 57th and 8th Mountain divisions) ensured the security of Assam, Arunachal, Monipur, Mizoram, Tripura and Nagaland.
April 1971: Indian Intervention in Bangladesh Maj. Gen. Rao Farman Ali and Lt. Gen. Sahabzada Yaqub Khan had expected that military action against Bengali civilians would result in Indian intervention, which the Pakistan army was woefully unprepared to meet in March 1971. The 14th infantry division with its brigades posted at Comilla (53rd), Dhaka (57th), Rangpur (23rd) and Jessore (107th) was the only Pakistani unit in East Pakistan prior to March 1971. The issue of direct military intervention was discussed between the Indian military and political leadership in April 1971. Although some Indian officers expected early intervention, Indian army command decided against immediate intervention, and concluded that a full attack could only take place after 15 November at the earliest, and only after deliberate and extensive preparations. The Indian Army Eastern Command took over responsibility for East Pakistan operations on 29 April, and on 15 May launched Operation Jackpot, a full-fledged operation to arm, train, equip, supply and advise the Mukti Bahini fighters engaged in guerrilla warfare against the Pakistan armed forces.
Indian Army Eastern Command draft plan: May 1971 Indian Eastern Command began drafting an operational plan for military action in Bangladesh from May 1971. Indian planners assumed that Pakistani army would try to defend the whole of the province to prevent Mukti Bahini from establishing the government inside Bangladesh. The main objectives of the May draft plan were:
The capture of Dhaka was the final goal. A winter campaign would reduce the chance of Chinese intervention as passes over the Himalayas would be snowed shut and the ground in Bangladesh would be firm and most favourable for armour and mechanised movements. Some troops deployed on the Chinese border can be used in Bangladesh. October – April period was the best time to launch an offensive, while the Monsoon rains (May – September) turned the country into a morass. Axis of advance should aim to isolate and bypass Pakistani forces – which meant a minimum superiority in numbers was needed. Fortified positions should be bypassed. Subsidiary objectives should be picked to occupy communication centres and destroy Pakistani command and control ability. Preliminary operations (by Mukti Bahini and then Indian forces) should aim to draw the Pakistani forces near the border, so key areas in the interior are left undefended.
Proposed axis of advance Eastern Command had concluded that The major rivers divided Bangladesh into 4 sectors:
North – Western Sector (Pakistani designation Northern Sector): The area north of the Padma and west of the Jamuna river. Bogra was the main communication hub and the sector is connected to the western sector through the Hardinge Bridge. The Shiliguri corridor, which is vital for road and rail communication with Eastern India, borders the northern tip of this sector.
A division size attack along the Hili – Gaibandha axis, expected to be heavily defended, aimed to capture Bogra. Later an alternative road was identified, and it was decided to launch a secondary attack on Hili while the main attack bypassed Hili, along the Parvatipur – Phulbari – Pirganj – Palashbari – Bogra axis. Two brigade groups were to operate from Shiliguri area and from Cooch Bihar as needed.
Western Sector (Pakistani designation Western Sector): This area lies south of the Padma and west of the Meghna. The main communication hub is Jessore, along with Jhenaidah and Magura, and Khulna is a vital sea port. From Jessore a road runs east to Faridpur, and via ferry it is possible to approach Dhaka.
Two divisions were to attack along the Boyra – Garibpur – Jessore and Darshana – Kotchadpur – Jhenaidah axis. The natural thrust lines along the Benapol – Jessore and Meherpur – Chuadanga – Jhenaidah, were expected to be heavily defended and was not considered. An infantry brigade was to move along Murshidabad – Kushtia line, capture the Hardinge bridge, then move south to Jhenaidah. Then the whole force would move towards Magura, cross the Madhumati and capture Faridpur. With the help of the Inland Waterways Flotilla, an assault towards Dhaka across the Padma would be launched.
North Eastern Sector (Pakistani designation Dhaka Bowl): This area sits to the east of river Jamuna, north of Padma and west of the Meghna and contains the city of Dhaka. A branch of the Jamuna flows to the north of Dhaka between the Jamuna to the Meghna rivers, while a rail bridge at Bhairab connects this area with the south eastern sector.
A division would advance along the Kamalpur – Jamalpur –Tangail – Dhaka axis. An additional brigade would support the advance while a Para battalion could be airdropped to Tangail to cut off Pakistani forces.
South Eastern Sector (Pakistani designation Eastern Sector): This lies to the east of Meghna, contains Sylhet, Comilla and the main seaport Chittagong. Control over Ashuganj, Chandpur and Daudkandi was vital to approach Dhaka.
3 divisions were to secure the area between Ashuganj and Chandpur, then if possible approach Dhaka by crossing the Meghna using helicopters or ferry – whichever was available. Indian Navy would blockade Chittagong.
Mukti Bahini support was expected in all phases of the operation.
Proposed Force allotment Indian Army HQ initially allocated the 9th infantry division, 4th Mountain division, the 50th Para Brigade (army HQ reserve), and the 340th brigade group for operations in the east alongside whatever forces Indian Eastern Command could assemble. Eastern command proposed the following allocation of forces:
1. The XXXIII corps would guard the Shiliguri corridor with the 71 Mountain brigade, which could also move against the North Western Sector, while the 20th Mountain division and the 340th brigade would bear the brunt of the fighting. The 3rd armoured brigade can also be employed as needed.
2. The IV corps (8th, 57th and 23rd mountain divisions) would be responsible for the South Eastern Sector, while a rear HQ looked after Assam, Mizoram, Nagaland and the Chinese border.
3.A new corps (4th Mountain and 9th divisions) was slated for the Western Sector operations.
4. The 6th Mountain (part of Army HQ reserve designated for operations in Bhutan against Chinese moves) and the 9th Mountain brigade would be used in the North Eastern Sector.
Seven divisions, 3 independent brigade groups, one armoured brigade and the Mukti Bahini was earmarked for the draft plan, which was shared with the DMO, Lt. Gen. K.K. Singh. During May – November, while Mukti Bahini engaged Pakistani forces, Eastern Command, having never contemplated or anticipated large scale military action against East Pakistan began building up logistical infrastructure while army support services (Engineer, Ordnance and Medical) began to build up capacity to sustain a 4 week long campaign.
Mukti Bahini plan: July 1971 General M.A.G. Osmani (Commander in Chief Bangladesh Forces) had differences of opinion with the Indian leadership regarding the role of the Mukti Bahini in the conflict. Indian leadership initially envisioned Bengali forces to be trained into a small elite guerrilla force of 8,000 members led by the surviving East Bengal Regiment soldiers operating in small cells around Bangladesh to facilitate the eventual Indian intervention, but the Bangladesh Government in exile and General Osmani favoured the following strategy:
1.Bengali conventional force would occupy lodgment areas inside Bangladesh and then Bangladesh government would request international diplomatic recognition and intervention. Initially Mymensingh was picked for this operation, but Gen. Osmani later settled on Sylhet.
2.Sending the maximum number to guerrillas inside Bangladesh as soon as possible with the following objectives:
Increasing Pakistani casualties through raids and ambush Cripple economic activity by hitting power stations, railway lines, storage depots and communication networks. Destroy Pakistan army mobility by blowing up bridges/culverts, fuel depots, trains and river crafts. The strategic objective is to make the Pakistanis to spread their forces inside the province, so attacks can be made on isolated Pakistani detachments.
Bangladesh was divided into Eleven sectors in July while 3 brigades (8 infantry battalions and 3 artillery batteries) were put into action between July – September. During June –July, Mukti Bahini had regrouped across the border with Indian aid through Operation Jackpot and began sending 2000 – 5000 guerrillas across the border, the so-called Monsoon Offensive, which for various reasons (lack of proper training, supply shortage, lack of a proper support network inside Bangladesh etc.) failed to achieve its objectives. Bengali regular forces also attacked BOPs in Mymensingh, Comilla and Sylhet, but the results were mixed. Pakistani authorities concluded that they had successfully contained the Monsoon Offensive, and they were not far from the truth.
Pakistani defence plan: June 1971