Eastern Command, 3 October to 26 November 1971

Headquarters Eastern Command (India) had in the meantime set up a series of wireless interception stations to lock on to radio transmissions between Karachi, Lahore, Rawalpindi and Dhaka. General Jacob believed that “being warned was being forearmed”. These wireless intercepting stations had been set up in September 1971.

All intercepted transmissions were encrypted in high-level codes, and all that the Indians had was a mass of encrypted data on the spools of their Grundig tape recorders. The encrypted information made no sense whatsoever. It was now early November, and General Jacob was desperately looking for something meaningful to link the stray bits of information that would help him to connect the pieces of the jigsaw puzzle and understand what the Pakistanis were up to.

On 8 November, Major Dharam Dev Datt, the officer commanding one of the intercepting wireless stations, was the image of concentration as he slowly turned the knobs of the Racal RA 150 radio receiver in an attempt to latch on to the messages between Karachi and Dhaka. A sudden increase in the number of messages on that day meant that there was something big in the offing, and it was crucial that India got to know what the Pakistanis were up to as early as possible.

General Yahya Khan had been making statements like, “I am going to teach India a lesson that she will never forget” and “In a few days I shall be away fighting a war.” War with Pakistan therefore seemed a certainty, and it was necessary that India got to know when and where Pakistan would launch her offensives on land and sea, and from the air.

So far, nothing was known – just a mass of hieroglyphics that made no sense and small snatches of conversation that had no meaning. On 9 November, however, an interesting development was about to take place.

Dharma’s intuition told him that something important was on the horizon, and although twelve hours had passed, he had not gone home. Better known as 3D, he had been continuously on the radio receiver looking for the elusive breakthrough. (Dharam was called 3D because his name in official records was Dharam Dev Datt – a long name which was reduced to “3D” by a senior cadet at the National Defence Academy, and the name had stuck.)

Sangeeta, his wife, had sent a towel and a change of clothes, and he had a cold bath in the toilet of his office. He was, however, once again perspiring, and this was due more to the tension rather than the weather. Dharam was a “go-getter”. He had lost a leg in counterterrorist operations, but that had made him even more determined to prove that he was as competent as non-disabled officers. Given a task, he would not rest till he had completed it successfully.

One more day and a night had passed with no breakthrough. 3D had by now been continuously on his radio set for the last thirty-six hours, with short breaks in between, and he was beginning to tire. Whatever messages he was intercepting, were being recorded and copied and sent across to the cryptographers. It was important that all messages were recorded and stored. The unravelling of the content of these messages would take place later.

He had some of the best cryptographers in the service. The discs of the tape recorder rotated and stopped intermittently in accordance with the length of the messages that were flying through space across the Indian landmass that separated West and East Pakistan, but the content of the messages was still a mystery. The tape recorders were linked with an IBM mainframe computer, and the cryptographers in the adjacent room were hard at it, trying to break the codes of the cryptograms routed to them by 3D.

His team had been working in shifts and there were some small successes, but the key to the code had continued to elude them. Suddenly, on the evening of 10 November, the Pakistan Naval code was broken and everything fell into place. All the messages of the past few weeks would be decoded, scrutinised and passed on to the relevant departments of the army, navy and air force.

3D immediately rang up Major General Jacob. He had direct access to the General with orders to speak to him at any time if anything important came up. 3D gave General Jacob the code word that signified that the Pakistan Naval code had been broken. The general was quietly elated. His intuition and anticipation had begun to pay off. He knew that with the breaking of the Pakistan Naval Code, he now had the upper hand to plan his strokes and counterstrokes.

“Good show, Dharam,” he said. “Just make sure that no one comes to know about this. No one means no one! Neither the Pakis nor us! If this becomes known in the wrong quarters, then all our work would be in vain!”

“Yes, sir!” said Dharam and quickly passed orders forbidding anyone from babbling that the Pakistan Naval code had been broken. The breaking of the Pakistan Naval code revealed that Pakistan was moving inexorably towards war. It was clear from the decoded messages that the primary objective of the Pakistan Navy was to destroy INS Vikrant, India’s aircraft carrier and the prized warship of the Indian Navy. Pakistan’s secondary objective was to use its state-of-the-art Daphne-class submarines – the Hangor, Sushuk and the Mangro – to destroy the warships of India’s Western Fleet, in Bombay harbour.

1971: Stories of Grit and Glory

Excerpted with permission from 1971: Stories of Grit and Glory from the Indo-Pak War, Ian Cardozo, ebury.