In mountains, fight is always for the peaks since they dominate a wide area all around, you dominate in terms of observation as well as fire.
A buildup in the face of an enemy who is on the peaks cannot be hidden for long. Surprise is difficult to achieve, unless infiltration is resorted to, that too in small groups. 2 Naga, 18 Grenadiers and 8 Sikhs, as part of 192 Brigade, had to face the same kind of domination during their assaults on Tiger Hill.
The defender can easily reinforce his defences if he gets even a whiff of a buildup. (Poonch 1971, 12 Division's 2 brigade attack against Indian 2 brigades)
In simple words, if you have to attack, then you must aim to to capture a peak quickly, then must open the logistics route so tthat the newly captured ground is able to sustain the counter attacks of the defender.
Remember, the defender is already taxed since he has to attack uphill to regain his lost position. He can only succeed if he can deny the attacker on the top urgently needed re-supply of ammo and heavy weapons. If defender can deny that, then with support of heavy artillery ofcourse to keep the heads down of the people at top, he has some chance of success.
LOC is already full of salients and bulges at present. They are being held just because the defences at the tops have been fortified and well stuffed supplies to last for weeks.
While India can induct reinforcements into the sector in wartime, Pakistan may not be able to spare much because of its army is much smaller. Nonetheless, compared to earlier wars, Pakistan is far better off even allowing for land’s reinforcements.
India might seem to have many opportunities to attack in this sector because of its superior strength. The problem is that the Indian line of communications runs very close to LOC. The loss of the road itself would not be fatal because:
All formations have large reserve stockpiles of equipment to enable them to fight for many months..and..
Air re-supply is available on a considerable scale.
The location of existing roads and the need to protect them force India into some very predictable moves. For example, IA always has to attack from Kargil and from Dras to push the PA as far back as possible. This predictability limits IA flexibility and prevents the achievement of surprise.
Moreover, still the force to space ratio in this area is very low. This is to say that given the length of the front, the number of troops is insubstantial. This should provide excellent opportunity for maneuver. The high mountains, however, impose severe constraints on which areas can be used for operations.
While India has good lateral east- west communications, Pakistan has good north-south communication through the river valleys. It is easier for IA to defend than to attack: but the converse is true for Pakistan.
Historically, the only fighting that resulted in strategic gains in North Kashmir took place in 1947-48. Initially, there were no Indian regular troops in the area, and the few levies of the Maharaja of Kashmir proved ineffective. The area was considered inaccessible, though this did not stop the Azad troops from capturing it. India could not even spare a single regular battalion as Army HQ was totally focused towards the valley. This omission, however logical it may have appeared at that time, was to cost us IA badly, especially after the Pakistan-China ties warmed up.
India started to worry about the area only in the late 1950s, when trouble with China began brewing. Then it was discovered that holding Ladakh while simultaneously protecting the cease-fire line against Pakistan was a tough proposition, which it remains to this day.
Both in 1965 and 1971 there were no strategic gains in this sector. Fighting took place for piquets dominating the Leh road. In both cases India did better than Pakistan, because Pakistan depended on the ruggedness of the terrain and therefore had committed few resources. IA had large numbers of regular troops, Pakistan had none.
Coming back to mountain terrain.....
Take the example of 19 Division (IA).
If we conceive this sector as the left half of a lady’s Chinese fan, we see that the roads from the fan’s hinge (Srinagar) to the periphery (Uri, Tithwal, Gurais) are excellent, but that the links along the periphery are inadequate or non-existent. Thus, reserves from Srinagar and Baramula can be sent quickly to Uri, Tithwal and Gurais, but there can be no movement between these three sectors without first returning to the Valley.
This creates the worst possible situation for a military commander: his forces are deployed as long fingers and no finger can support the other. Each sector must fight its own battle and must, then, be correspondingly self-sufficient in forces.
Pakistan, on the other hand, has excellent lateral communications. It holds a shallow part of mountainous Western Kashmir with the plains behind. So it can switch forces and concentrate at will at any point along the line between Jammu and Tithwal.
This gives PA the initiative in the entire area.
Nonetheless, India holds one advantage not enjoyed by Pakistan. IA has to attack downhill, whereas Pakistan has to move uphill.
The complication in all the Jammu and Kashmir sectors is the political importance of the ground. No first strike can be countered without giving up some ground. In Jammu and Kashmir every square kilometre lost no matter what the reason is held against the commander with his superiors and their political superiors.
This unfortunate situation should have been corrected years ago.
The only remedy then becomes to over-ensure in each sector, and to maintain troops right on the line, holding every kilometre as closely as possible, even though this involves violating the principles of war relating to surprise and economy of force. There can be no economy or concentration of force because the enemy is aware of your compulsions to avoid giving up ground, and can, therefore, accurately predict your actions.
This, however, is only one of the two reasons (FOR IA) why such large forces have to be mentioned along LOC. The other, seldom openly stated, is the perceived need to contend with a hostile domestic population in wartime.
The battle will, then, be on two fronts. Take the example of 161 Brigade. Normally, it has the usual five regular and one BSF battalion. The Brigade commander, however, does not regard his forces as equal to 2/3rds of a division. He allots three infantry battalions, a normal brigade, to the front. And he allots the other three battalions to keep open his Line of Communications, with Baramula, 60 kms away.
So the commander, 161 Brigade has, from his viewpoint, only the minimum number of troops required for his job. Given the importance of the ground, we may speculate he would like a minimum of another regular battalion. And the Indian Army, at least, is no stranger to seven battalion brigades.
Because of the mountainous terrain, however, neither side is likely to achieve major gains. As a caveat it should be said that if one side makes a breakthrough for example, if Pakistan took Poonch or India took Kotli, depending on how panicked the defence becomes, it is possible the whole front will unravel and permit a strategic victory. But if both sides hold reasonably firm, neither side will make any strategic gain.
Mountain positions stoutly defended are virtually impossible to assault frontally. They are usually taken by a slow process of infiltration around the position, and then a surprise attack, say from three sides. Cutting roads behind and between positions is of the utmost importance. A brigade attacking battalion position can break through after some time, but not if reinforcements arrive. This not only takes time but, with active/aggressive patrolling the defender can prevent encirclement. The Central Italian campaign of 1944 is an excellent example of how difficult it is to take mountain positions. And, of course, the Italian mountains are quite geographically tame compared to ours.