The Indo-Pakistani War of 1965, also known as the Second Kashmir War, was the culmination of a series of skirmishes that occurred between April 1965 and September 1965 between India and Pakistan. The war was the second fought between India and Pakistan over the region of Kashmir, the first having been fought in 1947. The war lasted five weeks, resulted in thousands of casualties on both sides and ended in a United Nations (UN) mandated ceasefire. It is generally accepted that the war began following the failure of Pakistan's Operation Gibraltar which was designed to infiltrate and invade Jammu and Kashmir.

Much of the war was fought by the countries' land forces in the region of Kashmir and along the International Border (IB) between India and Pakistan. This war saw the largest amassing of troops in Kashmir, a number that was overshadowed only during the 2001-2002 military standoff between India and Pakistan. Most of the war was fought on land by each country's infantry and armored units, with substantial backing from their air forces. Many details of this war, like those of most Indo-Pakistani Wars, remain unclear and riddled with media biases.

Since Independence, both nations were in contention over several issues, primarily on border disputes. Kashmir was a major divisive issue between both the nations, but other border disputes existed, most notably over the Rann of Kutch, a barren region in the Indian state of Gujarat. Though the erstwhile princely state of Junagadh was integrated into India, its borders, especially in the marshlands to the west were ambiguous. This gave rise to a dispute between Pakistan and India. On March 20 1965, and again in April 1965, fighting broke out between India and Pakistan in the Rann of Kutch. Initially involving the border police from both nations, the disputed area soon witnessed intermittent skirmishes between the countries' armed forces. In June the same year, British Prime Minister Harold Wilson successfully persuaded both countries to end hostilities and set up a tribunal to resolve the dispute. The verdict, which came later in 1968, saw Pakistan gaining 350 square miles (900 km²) of the Rann of Kutch, as against its original claim of 3500 sq miles.

After its successes in the Rann of Kutch, Pakistan, under the leadership of General Ayub Khan, is said to have believed that the Indian Army was unable to defend itself against a quick military campaign in the disputed territory of Kashmir, following a loss to China in 1962.Pakistan believed that the population of Kashmir was generally discontented with Indian rule and that a resistance movement could be ignited by a few infiltrating saboteurs. This was codenamed Operation Gibraltar.[8] However, the Pakistani infiltrators were soon discovered, aided primarily by the local Kashmiris themselves and the entire operation ended in a complete disaster.

For its part, Pakistan claimed to have been concerned by the attempts of India to absorb Kashmir - a state that Pakistan claims as "disputed", into the Indian union by way Articles 356 and 357 of the Indian Constitution allowing the President of India to declare President's Rule in the disputed state.

The war

On August 15, 1965, Indian forces crossed the ceasefire line and launched an attack on Pakistan administered Kashmir. Pakistani reports cite this attack as unprovoked. Indian reports cite the attack as a response to the massive armed infiltrations by Pakistan. Initially, the Indian Army met with considerable success in the northern sector (Kashmir). After launching a prolonged artillery barrage against Pakistan, India was able to capture three important mountain positions. However, by the end of the month both sides were on even footing as Pakistan had made progress in areas such as Tithwal, Uri and Punch and India had gains in Pakistan Administered Kashmir (sometime referred as Pakistan Occupied Kashmir), having captured the Haji Pir Pass eight kilometers inside Pakistani territory. Following the failure of Operation Gibraltar, that resulted in territorial gains and rapid Indian advances in Kashmir, Pakistan launched a bold counter attack on September 1, 1965 to reclaim vital posts in Kashmir lost to India. This attack, called "Operation Grand Slam" was intended to capture the vital town of Akhnoor in Jammu and thus sever communications and cut off supply routes to Indian troops. Attacking with an overwhelming ratio of troops and technically superior tanks, Pakistan was on the verge of springing a surprise against Indian forces, who were caught unprepared and suffered heavy losses. India then called in its air force to target the Pakistani attack in the southern sector. The next day, Pakistan retaliated, initialising its air force to retaliate against Indian forces and air bases in both Kashmir and Punjab. But Operation Grand Slam failed to achieve its aim as the Pakistan Army was unable to capture the town. This became one of the turning points in the war, as India decided to relieve pressure on its troops in Kashmir by attacking Pakistan further south.

India crossed the International Border (IB) on the Western front on September 6, marking an official beginning of the war. On September 6, the 15th Infantry Division of the Indian Army, under World War II veteran Major General Prasad battled a massive counterattack by Pakistan near the west bank of the Ichhogil Canal (BRB Canal), which was a de facto border of India and Pakistan. The General's entourage itself was ambushed and he was forced to flee his vehicle. A second, this time successful, attempt to cross over the Ichhogil Canal was made through the bridge in the village of Barki, just east of Lahore. This brought the Indian Army within the range of Lahore International Airport, and as result the United States requested a temporary ceasefire to allow it to evacuate its citizens in Lahore. One unit of the Jat regiment, 3 Jat had also crossed the Ichogil canal and captured the town of Batapore (Jallo Mur to Pakistan) on the west side of the canal, threatening Lahore on the very start of the war.

The same day, a counter offensive consisting of an armored division and infantry division supported by Pakistan Air Force Sabres rained down on the Indian 15th Division forcing it to withdraw to its starting point. Although 3 Jat suffered minimal casualties, the bulk of the damage being taken by Ammunition and stores vehicles, the higher commanders however, had no information of 3 Jat's capture of Batapore and misleading information led to the command to withdraw from Batapore and Dograi to Ghosal-Dial. This move brought extreme disappointment to Lt-Col Desmond Hayde, CO of 3 Jat. Dograi was eventually recaptured by 3 Jat on 21 September, for the second time but after a much harder battle due to Pakistani reinforcements.

On the days following September 9, both nations' premiere formations were routed in unequal battles. India's 1st Armored Division, labelled the "pride of the Indian Army", launched an offensive towards Sialkot. The Division divided itself into two prongs and came under heavy Pakistani tank fire at Taroah and was forced to withdraw. Similarly, Pakistan's pride, the 1st Armored Division, pushed an offensive towards Khemkaran with the intent to capture Amritsar (a major city in Punjab, India) and the bridge on River Beas to Jalandhar. The Pakistani 1st Armored Division never made it past Khem Karan and by the end of September 10 lay disintegrated under the defences of the Indian 4th Mountain Division at what is now known as the Battle of Asal Uttar (Real Answer). The area became known as 'Patton Nagar' (Patton Town) as Pakistan lost/abandoned nearly 100 tanks mostly Patton tanks obtained from the United States.

Pakistan was taken aback by the lack of support by the United States, an ally with whom the country had signed an Agreement of Cooperation. The United States declared its neutrality in the war by cutting off military supplies to both sides. After the war, Pakistan would increasingly look towards China as a major source of military hardware and political support. Another negative consequence of the war was the growing resentment against the Pakistani government in East Pakistan. Bengali leaders accused the government for not providing adequate security for East Pakistan during the conflict, even though large sums of money were taken from the east to finance the war for Kashmir. In fact despite some PAF attacks being launched from East Pakistan (present day Bangladesh) during the war, India did not retaliate in that sector, although East Pakistan was defended only by a two-infantry brigade division (14 Division) without any tank support.Sheikh Mujibur Rahman was apprehensive of this situation, and the need for greater autonomy for the east led to another war between India and Pakistan in 1971.