Practice of using heavy tanks and SPGs in combat showed that IS-122 and ISU-152 are the best method of fighting enemy heavy tanks and can deal great damage to the enemy when used carefully and skilfully.
Careless use of the IS and ISU tanks result in pointless losses, such as:
- The commander of the 141st Infantry Division positioned the 29th Tank Regiment (IS-122) in the front line of defense, as a result of which the regiment pointlessly lost 8 tanks.
- The commander of the 17th Mechanized Brigade moved ISU-152 tanks ahead of infantry at Mihalkiuv and Ezefuvka, losing 3 tanks.
- Frequent movement of tank regiment wastes engine-hours, which causes tanks to break down earlier. The 374th Guards Heavy SPG Artillery Regiment that was formed on April 4th, 1944, expended 160-180 engine-hours by May 12th.
- The main purpose of heavy tank and SPG regiments is to fight enemy heavy tanks and SPGs and suppress pillboxes.
- During offensives, use IS-122 and ISU-152 regiments as follows: heavy tanks follow medium tanks in the second echelon, 300-500 meters behind. The front of one regiment is 1000-1500 meters wide.
Heavy tanks should be protected by T-34s and SPGs from the flanks. In addition, each IS-122 and ISU-152 must be protected by submachinegunners.
Some heavy tanks or SPGs may be included in assault groups. In this case, they are attached to independent regiments and broken up into assault battalions. Tanks are carefully used depending on terrain and attack pillboxes in assault groups, suppressing the pillboxes by fire from a range of 1500 meters or closer.
- During defense: position IS or ISU regiments in a checkerboard pattern across a 2.5 km wide and 2 km deep front.
The first line of defense is made up of infantry, artillery, and medium tanks. 500-600 meters behind them are two or three companies of IS or ISU tanks. 800-1000 meters behind them are the rest of the tanks of the regiment, used as a mobile reserve. IS and ISU regiments must always be used in combination with supporting tanks.
When tanks fight from ambushes, commanders must personally observe the enemy. As soon as enemy tanks appear, the tanks must take up firing positions such that only a part of the turret is shown.
Open fire from 1500 meters or closer to guarantee accuracy and rapid destruction of enemy tanks.
When deflecting enemy tank attacks, acting in pairs is the best method. One tank fires upon the enemy tanks, the other watches enemy tanks from cover. With his maneuver and fire, he supports the actions of the first tank.