A few more questions. What was India's claimed line or the "cartographic expression" line north of NJ9842, pre 1984?
Indian claim line has always been "thence north to the glaciers" as per the Shimla Agreement. Contrary to popular perception, there are three actors in this Cartographic Aggression - Pakistan, China and USA.
(a) First act - Sino-Pakistan Boundary Agreement - it was through this agreement that Pakistan ceded the Trans-Karakoram Tract or Shaksgam Valley to China. Here is the link to the agreement:http://www.tpprc.org/documents/agreements/1963-A.pdf
Last para of the agreement reads thus:
Thence, the boundary line, running generally southward and then eastward, strictly follows the Karakoram range main watershed which separates the Tarim river drainage system from the Indus river drainage system, passing through the east Mustagh pass (Mustagh pass), the top of the Chogri peak (K-2), the top of the broad peak, the top of the Gasherbrum mountain 8068, the Indirakoli pass (names on the Chinese maps only) and the top of the Teram Kankri peak, and reaches its southeastern extremity at the Karakoram pass
While Pakistan was physically in possession of land in Northern Areas, it could well enter into agreement with China on demarcating and settling the boundary between Northern Areas and Chinese Turkestan. But on what basis did it demarcate the line east of Mustagh Pass and said that the alignment ran till Karakoram Pass? It would not have done this unless it considered these areas as part of Pakistan/Northern Areas.
And there is an evidence to this - from wiki:
In 1957 Pakistan permitted a British expedition under Eric Shipton to approach the Siachen through the Bilafond La, and recce Saltoro Kangri. Five years later a Japanese-Pakistani expedition put two Japanese and a Pakistani Army climber on top of Saltoro Kangri. These were early moves in this particular game of oropolitics.
(b) ADIZ (Air Defense Identification Zone) Map - this is the real culprit. Again from wiki:
The United States Defense Mapping Agency (now National Geospatial-Intelligence Agency) began in about 1967 to show, with no legal or historical justification or any boundary documentation, an international boundary on their Tactical Pilotage Charts available to the public and pilots as proceeding from NJ9842 east-northeast to the Karakoram Pass at 5,534 m (18,136 ft) on the China border. Numerous governmental and private cartographers and atlas producers followed suit. This resulted in the US cartographically "awarding" the entire 5,000 square kilometers (1,900 sq mi) of the Siachen-Saltoro area to Pakistan.
Here is the ADIZ Zone map taken from the presentation by Gurmeet Kanwal and ex-PA officer:
I have a theory as to how the above could have happened - As the Sino-Pakistan Boundary agreement was up to Karakoram Pass and the last drawn reference on the 1949 CFL Agreement was til NJ9842, some analyst sitting in USA would have done the obvious and drawn an straight line in NE Direction connecting NJ9842 with KK Pass. And pakees being true pakees, simply grabbed at the opportunity.
BTW, definition of ADIZ is as follows:
An air defense identification zone (ADIZ) is an area of airspace defined by a nation within which "the ready identification, the location, and the control of aircraft are required in the interest of national security". Typically, an aircraft entering an ADIZ is required to radio its planned course, destination, and any additional details about its trip through the ADIZ to a higher authority, typically an air traffic controller.
So, there was no doubt in the mind of the person who was drafting the ADIZ Map.
Are there ANY validating references to the fairly new statement by Lt. General Prakash Katoch (retd), that Pakistan violated an agreement on Gyong La in 1987? This is a pass that always was in Pakistani control as 19 Kumaon Column, could not reach there in time on foot, due to an avalanche?
Well, this is a case of "Bagal mein chora, gaon mein dhindora" - the excellent article on BRM has the source - here goes:
I handed over command of the 10 Corps to Lieutenant-General Zahid Ali Akbar Khan on 31st March 1984 after completing my tenure of four years. I gave him a detailed briefing about this operational plan and particularly stressed the importance of Intelligence keeping a watch on Indian moves beyond Leh. However, I learned later that when our troops approached the Baltoro Ridge passes during the third week of May 1984, the Indians were already in occupation of Gyong Pass in the south, strategically important because it could interfere with the enemy's line of logistic support. As it was impossible to dislodge the Indians, we had no option but to occupy the next highest feature opposite them. This was a great setback for Pakistan, although all plans, including the timing of troop movement, had been laid down at the highest level. We had obviously failed to appreciate the timing of the Indian move and our intelligence agencies had failed to detect the movement of a brigade-size force in this area. It was learnt that the Indians had moved up their troops from Leh in the second half of April 1984.