The predecessors of the JS-1 and JS-2 tanks were the KV-1 Heavy Tank and KV-13 Heavily Armored Medium Tank. KV-13 (and its subsequent version - Object 233) became the first major independent project of the Experimental Tank Factory, created in March 1942 in Chelyabinsk from Design Bureau No.2. N.V.Tseits, who had been recently released from a GULag, was appointed head designer of the project.
Other members of the design team were K.I.Kuzmin (hull), N.M.Sinev (turret), S.V.Mitskevich (chassis) and G.N.Moskvin (general assembly). KV-13 was designed as a universal tank - medium tank weight and heavy tank protection. This project was distinguished by its extensive use of cast armour. Casting was used not only for the turret, but also for the main elements of its hull - the glacis, turret ring and rear.
This reduced the usable internal space, but increased the effective armour protection whilst reducing the amount of armour needed for its manufacture. The last point was especially important in light of the State Defense Committee's decree of 1942 to minimise the consumption of armour materials.
The first test unit was designed and produced in an extremely short period of time and in May of 1942 it was delivered to the factory testing facilities. The tank weighed 31.7 tonnes and was armed with a 76.2 mm ZiS-5 gun and a coaxial DT TMG.
The maximum front armour thickness of its hull was 120 mm, that of its turret - 85 mm. Its V-2K 600 h.p. engine allowed it to reach speeds of up to 55 km/h. Elements of the T-34's chassis, including tracks, were used, whilst the road wheels were taken from the KV.
The KV-13 had an improved (U-shaped) radiator similar to the one previously used on the Kirov Factory variant of the T-50 tank. This allowed for a more efficient engine block configuration and also increased the efficiency of its air intake.
Several flaws surfaced during the testing of the first experimental unit of the KV-13: poor acceleration due to transmission problems, tracks and rollers easily damaged, tracks being thrown while making turns, etc. In July 1942, in the middle of its testing, the head designer N.V.Tseits died and N.F.Shamshurin was appointed in his place. On his initiative the KV-13 received the transmission developed by F.A.Marishkin for the KV-1S, as well as some other parts of its chassis. However, even after these improvements, the tank did not pass its tests and the military quickly lost interest in it.
Despite these early failures, in December of 1942 the assembly of two new variants of the KV-13 began at the Experimental Tank Factory. The new vehicles shared only the hull, torsion bar suspension, and chassis from the first version. The turrets and many other elements were completely new designs. The transmission used was significant in its use of a planetary 2-step travesing gear designed by A.I.Blagonravov. The cooling system was improved, while the track links were lightened by making every other link flat (the so-called "Chelyabinsk tracks").
The appearance of the German heavy Tigers on the Eastern Front played a direct and decisive role in increasing the speed of development of these new models. According to decree No.2943ss of the GOKONKTP were to manufacture two experimental tanks of the "Josef Stalin" (JS) class (based on the two latest models of the KV-13) and prepare them for testing. (February 24, 1943) the Kirov factory in Chelyabinsk and factory No.100 (the new name of the Experimental Tank Factory) of of NKTP were to manufacture two experimental tanks of the "Josef Stalin" (JS) class (based on the two latest models of the KV-13) and prepare them for testing.
Both models were tested between March 22 and April 19, 1943 and in general performed quite well. The state commission noted that both JS tanks weighed less than the KV-1S, could achieve higher speeds, had better armour protection and had equal (JS-1) or better (JS-2) armament.
During testing, serious defects were discovered, particularly with the chassis and engine/transmission. It was also noted that when moving over soft ground the tanks experienced high rolling resistance due to their treads flexing into the space between the road wheels. The commission recommended increasing the number of road wheels on future test units of JS tanks.
At the same time preparations for production of the new vehicles began at the Chelyabinsk Kirov Factory (ChKZ), Factory No.100 and their main partner factories- the Ural Factory of Heavy Machinery (UZTM) and Factory No.200. However, further developments forced major changes in these preparations. In early April, the first reliable data on the armour protection of the Tigers was obtained. On April 15, 1943, the GKO issued the decree No.3187ss instructing the People's Commissariat for Armaments to develop more powerful anti-tank guns capable of destroying the new enemy AFV's.
At the end of April, a captured Tiger was brought to the Kubinka testing grounds to be subjected to firing tests. It turned out that the most effective weapon against it was the 85mm AA-gun 52-K model 1939, which penetrated the Tiger's 100 mm frontal armour from 1000 metres.
The GKO's decree No.3289ss of May 5, 1943, instructed the Design Bureaus to aim for the performance characteristics of that gun. Following this decree the Central Artillery Design Bureau (TsAKB), under V. G. Grabin, and the Design Bureau of Factory No.9, under F. F. Petrov, were entrusted with developing and installing new 85-mm guns on two KV-1S and two experimental JS tanks.
In the first half of June, four guns (two S-31s of the TsAKB and two D-5Ts of Factory No.9) were ready. The S-31 was the result of mating the 85mm barrel with the base of the 76.2mm ZiS-5 tank gun, which greatly simplified its manufacture. As for the D-5T, it was a variant of the D-5S gun developed for the SU-85 self-propelled gun and was characterised by its low weight and light recoil.
Right from the start it was obvious that it would be impossible to install an 85 mm gun in an unmodified JS turret without greatly degrading the crew's working space. It was therefore decided to increase the turret's dimensions, increasing the size of the crew compartment, which required the lengthening of the tank's hull by 420 mm.
An extra road wheel was added to compensate for the increased distance between the second and third road wheels. The new turret was cast at Factory No.200. All these changes resulted in an increase of the tank's weight to 44 tons and a reduction in its mobility. Such was the price of a more powerful gun. The JS with an 85mm gun was designated "Object 237". In the beginning of July 1943 two experimental vehicles - one with an S-31 gun and one with a D5-T gun - were produced.
At the same time the ChKZ prepared two designs for the installation of the 85mm gun on a KV-1S. The first variant - "Object No.238" - was a production KV-1S with a S-31 gun in its unmodified turret. The second - "Object No.239"- received the turret from "Object No.237" with a D-5T gun.
In July 1943, all four tanks underwent comparative test. Based on the results of these tests, the D-5T gun, Object No.237, and Object No.239 gave the best results and were accepted for serice, whilst "Object No.238" was cancelled due to the extremely small crew compartment hindering the normal functioning of the crew. Meantime both Object No.237, and Object No.239 were renamed as JS-85 and KV-85 respectively.
On July 31 the KV-85 and JS-85 were delivered to the Kubinka proving grounds for tests, accompanied by twenty eight engineers led by the chief engineer of Factory No.100, Mr. N.M.Sineev. The tests were started on August 2 by the Commission under the head of the Technical Administration of the Red Army, Major-General S.A.Afonin. The artillery tests were performed at the Gorokhovetsky Proving Ground. Based on the results, the Commission recommended both tanks for production. On the 8th of August, a column of experimental AFVs passed through the streets of Moscow into the Kremlin. Here, they were examined by Stalin, Molotov, Voroshilov, Beria and others. Interestingly, for the purpose of this display, all the crew except the drivers were replaced by NKVD officers.
On the 4th of September 1943, the JS-85 heavy tank entered service with the Red Army as ordered by GKO decree No.4043ss. The same decree ordered Factory No.100 (in cooperation with the Technical Administration of the Red Army) to develop, manufacture and test an JS tank armed with a 122mm gun by October 15, 1943, as well as a self-propelled gun on the same chassis (JSU-152) by November 1, 1943.
The first person to suggest arming the JS tank with a gun larger than 85 mm was the Director and Chief Designer of Factory No.100, Zh.Y.Kotin. He realized in August 1943, after studying the results of the Kursk battle, that the most effective anti-tank weapon employed against German Tigers was the Corps 122mm Field Cannon A-19 Model 1931.
The designers at Factory No.9 came to the same conclusions as Mr. Kotin, and designed the D-2 Heavy Anti-Tank Cannon by marrying the A-19 barrel with the carriage of the Divisional 122mm Howitzer M-30.
This powerful weapon was ordinarily employed against heavy tanks as an anti tank gun. The barrel of the gun was built into the gun carriage of the M-30 and the resulting gun successfully passed its tests, it became possible to install the A-19 gun in a heavy tank by using recoil-absorbers, elevation mechanism, and other mechanisms from the Experimental 122 mm Tank Howitzer U-11. This was done in a similar fashion to the 85mm guns D-5T and D-5S, but it was also necessary to add a muzzle brake.
Having received the necessary design papers from Factory No.100, the Design Bureau of Factory No.9 promptly prepared a draft design for the A-19 gun in the JS-85 turret and sent it to Moscow with J.Kotin. The People's Commissar for Tank Industry V.A.Malyshev (A People's Commissar is like a Minister) liked the project and Stalin approved it. The JS tank with a 122 mm gun entered service with the Red Army on the release of GKO decree No.4479ss dated October 31, 1943. This decree also charged Factory No.9 with manufacturing a tank variant of the A-19 gun with a piston-type breech by November 11, 1943 (to be delivered for firing tests by November 27). At the same time the factory was ordered to start manufacturing this gun with a wedge-type breech in 1944. It was also decided to allow production of several 100 mm guns for testing on JS tanks.
The first example of the A-19 tank gun was ready on November 12, 1943 - the barrel of the D-2 gun was removed from the M-30 gun carriage and installed in the D-5T base after after reducing its diameter. The T-shaped muzzle brake design was borrowed from the D-2 gun. The unusual muzzle brake was intended to reduce the main disadvantage of any muzzle brake: when a shot is fired, a large cloud of dust is kicked up from the ground, revealing the position of the tank. The T-shaped muzzle brake was intended to minimise any dust plumes due to firing.
The JS-122 (Object No.240) passed the Government tests quickly and successfully. Thereafter, the tank was moved to one of the Moscow military testing grounds where it was demonstrated to K.E.Voroshilov. The tank's 122 mm gun was fired from 1500 metres at a captured German Panther tank.
The round hit the side of the Panther's turret, penetrating it cleanly and tearing the opposite side out at the welded seams, throwing it back a few metres. During these tests the muzzle brake of the A-19 blew up almost killing Voroshilov. After this accident it was decided to change the muzzle brake to a 2-chamber design similar to that used by the Germans.
The first part of production JS-1 tanks was delivered in October of 1943, and the JS-2 - in December. At the same time ChKZ continued to manufacture KV-85 tanks until the end of 1943.
In January of 1944 the last 40 JS-85s were manufactured at the ChKZ. After this, it produced only the JS-122. These mounted the new 122 mm Tank Cannon D-25T with a wedge-shaped semi-automatic breech, which allowed an increased rate of fire from 1-1.5 shots per minute to 1.5-2 shots per minute. In March 1944, the "German-type" muzzle brake was replaced with a better design from the TsAKB. At the same time, the JS-85 was renamed JS-1, and the JS-122 was renamed JS-2.
At this stage, the issue of the JS-2's armament was not completely resolved. The military was not satisfied with its low rate of fire and limited ammunition stowage - only 28 two-piece rounds (compared to the 59 one-piece rounds for the JS-1 and 114 one-piece rounds for the KV-1S).
Further, after the first encounters between the JS-2 and German heavy tanks, it turned out that the sharp-nosed 122 mm APHE round - BR-471 - could only penetrate the frontal armour of a Panther up to 600-700 metres. The less powerful frontal armour of a Tiger could be penetrated at distances up to 1200 metres. However, at such distances only very well trained and experienced gunners could score a hit. The vertical armour of a Tiger I, although thicker than that of a Panther, was more easily defeated by the sharp-nosed projectile of the JS-2 Main Gun, whilst it often ricocheted off the sloped armour of a Panther. Later, Soviet designers noticed the blunt-nosed projectiles worked fine against sloped armour. After several tests, designers revealed the effect of "normalisation". The powerful HE round, OF-471, when fired at German tanks, caused cracking and could even completely tear off the front armour plate at the seam weld. The first results of the IS-2 in combat (backed by the results of its tests at the Kubinka testing grounds in January of 1944) forced designers to look for new solutions to its problems.
However, in the summer of 1944, the problem of the poor AP performance disappeared. The performance of the D-25T gun of the JS-2 against the German tanks improved dramatically. The reports from the front described cases where the BR-471 APHE round 122 mm projectile fired from 2500 metres ricocheted off the front armour of a Panther leaving huge holes and cracks in it.
This was explained by an interesting change of circumstances in the Summer of 1944. The Germans experienced a shortage of manganese and had to switch to using high-carbon steel alloyed with nickel, which made armour very brittle, especially at the seam welds. The first encounters of JS-2 tanks with the Germans also showed that the front protection of its hull was not impenetrable.
In the beginning of 1944, an attempt was made to improve the protection of the JS-2 by tempering the front armour to very high hardness. In practice, it led to a drastic increase in the number of components needed for the hull and significantly increased the cost of the tank's production.
In March 1944, firing tests were conducted with a 76.2 mm Gun ZiS-3 firing at an JS-2 tank from 500-600 metres. The tank's armour was penetrated from all sides of the tank. Whilst while most of the projectiles did not penetrate the armour completely, they created major splintering and fragmentation inside the turret. This explains the considerable losses of JS-85 and JS-122 tanks during the Winter-Spring of 1944.
In February of 1944 the Central Scientific Research Institute No.40 (TsNII-40) was delegated the task of researching the armour protection of the JS-2 heavy tank. The research showed that, given the existing shape of the front of its hull, the tank would be invulnerable to penetration by any German 75-mm and 88-mm AP projectiles only if the hull's armour thickness were increased to at least 145-150mm (i.e. an addition of 20-30 mm thickness).
On the recommendation of the TsNII-40, new specifications for armour tempering and a new design for the front of the JS-2's hull were developed. The new hull, with a straightened glacis, preserved the same armour thickness while the plug-type driver's hatch was removed, greatly increasing its protection from the front. The glacis was sloped at 60 degrees from the vertical, which resulted in the German 88 mm KwK 36 gun being unable to penetrate it even at point-blank range when fired at a ±30 degrees angle.
However, the lower front hull armour plate, sloped at 30 degrees from the vertical, remained vulnerable. To increase its slope would require significant alteration to the layout and design of the driver's compartment. Since the probability of a hit on the lower part of the hull was low, it was decided to leave the design unchanged. From July 15 1944, spare tracks were attached to the lower hull to increase its protection. In May of 1944, the UZTM plant started manufacturing the new straightened welded hulls. Factory No.200 began making the new type of hulls from June of 1944, but these were cast, not welded. However, for a while, tanks with old and new hull-types were produced simultaneously.
As for the tank's turret, it turned out to be impossible to increase its armour protection. Designed for the 85 mm gun, it was completely balanced. After installing the 122 mm weapon, the turret became very unbalanced. The Design Requirements intended for an increase of its frontal armour thickness to 130 mm which would have unbalanced the turret even further and would have made a new traverse mechanism necessary. SInce all these changes required a complete redesign of the turret, they were all cancelled.
Nevertheless, the appearance of the turret was considerably changed in the process of its production. The first batch of tanks manufactured in 1943 had a narrow porthole through which the sighting telescope fits. After the installation of the D-25T Main Gun, it became almost impossible to use the telescopic sight, even though its breech was the same as that of the D-5T.
Starting in May of 1944, a new turret with a widened porthole was manufactured, which resulted in the sight being moved to the left. The armour protection of the tank's mantlet was improved and the armour thickness of the sides of the lower hull was increased.
The commander's cupola was shifted 63 mm to the left and the PT4-17 periscopic sight was changed to a MK-IV sight. A DShK anti-aircraft machine gun (designer P.P.Isakov) was installed on the commander's cupola. After that, no further significant changes were made to the turret until the end of the war.
Basic Modifications of the JS Series
Object 237 = JS-85 = JS-1
Object 239 = KV-85
Object 240 = JS-122 = JS-2
JS-10 = T-10
Please Note: JS-1 and JS-85 are designations for the same tank. JS-122 and JS-2 are designations for the same tank.
Combat employment of the JS tanks
In February of 1944 all existing heavy breakthrough tank regiments, which were equipped with KV tanks, were re-equipped according to the new TO&E. Simultaneously, some new units were formed. These units were equipped with the newest JS tanks. During formation they received "Guards" status (in advance of their combat inmortance). According to TO&E, these regiments (each with 375 men in total) consisted of: four tank companies of 21 tanks (5 tanks per company plus one commander's tank), an SMG infantry company called "tankodesantniki" (infantry which ride on tanks), one antia-ircraft battery, a sapper platoon, a medical platoon and a signal platoon.
A feature of the JS tank was that each crew consisted of two officers (lieutenants): a tank commander and a driver. Another two members held the rank of sergeant: a loader and a gunner. Unfortunately, not all crewmen had fought in heavy tanks (KVs and Churchills) before. Many tankers didn't have any experience and came from tank schools, sometimes after additional courses.
One of the first units involved in battle was the 13th Guards Heavy Breakthrough Tank Regiment. By February 15, 1944, that regiment arrived in the region of Fastov - Belaya Tzerkov' with 21 JS-1 tanks. It was ordered to support the 109th Tank Brigade in an assault on Lisyanka village (Ukraine).
This fighting took place during the Korsun-Shevcheskovsk Operation. The 109th Tank Brigade was an element of 16th Tank Corps which was attached to the 2nd Tank Army. This Army fought against the German 3rd Panzer Corps. A commander of the 13th Regiment detached one company of 5 JS-1's and sent them into action. At that moment all the tanks of 109th Brigade were knocked out by German Panthers and assault guns camouflaged somewhere in the village.
Soviet tanks approached within 600-700 metres, when the Germans opened fire. All the Soviet tanks were knocked-out; two of them were burned out. Each of the JS's received up to 7 hits. The next day Lisyanka was encircled and liberated. The Russians captured 16 abandoned Panthers, 2 Pz-IV and 2 StuG-40. They were abandoned after running out of fuel.
On March 15, 1944, fifteen JS-1's from the 13th Guards Heavy Breakthrough Tank Regiment were supporting an attack of 50th Tank Brigade near the Uman'. During that battle, five JS-1 were destroyed by German 88 mm Flak guns. Three tanks failed due to technical breakdowns, and one tank fell into a river (near Polkovnichie). During that battle a rare incident occurred: the lower frontal armor of an JS-1 was penetrated by a German Pz.B-41 anti-tank rifle.
The first verified engagement between JS-1's and Tigers I occurred on the 4th of March, 1944 near the Staro-Konstantinov (Ukraine). During the Proskurovsko-Chernovitsky offensive operation the 1st Guards Heavy Breakthrough Tank Regiment (of Colonel N.I.Bulanov) was involved in a battle with a company of Tigers of the 503rd PzAbt. One of the JS-1's was destroyed from a range of between 1500 and 1800 metres and another two were damaged in various ways though were capable to move.
The main gun of one of the Tigers was also damaged in the engagement. Another Tiger received heavy damage in the chassis. On March 16 of 1944, several Tigers ambushed a company of JS-1's. Two of the Soviet tanks were burned out with their crews. During 8 March, on a number of occasions, a couple of JS-1's were destroyed by a battery of 75 mm PaK 40's from the lethally short distance of 150-200 metres. The first JS received 8 hits and the second tank - 4 hits.
Analyzing the results of those battles, the GBTU came to the conclusion that the armament and protection of the JS-1 didn't correspond to its intended tasks and was inferior to the German heavy tanks. GBTU recommended increased armor protection and rearming the JS-1 with a more powerful weapon.
The JS-2 tank happened much more dangerous to German tanks because the 122 mm D-25T gun had better armour-penetration than the 85 mm D-5T. Furthermore, its fragmentation and high explosive ammunition was also quite effective against armored targets. Like the JS-1, the JS-2s had their "baptism of fire" during the final stage of liberation of the right-bank Ukraine.
It is necessary to remind readers that the first time the JS-2 saw the action was not in the Korsun-Chevchenkovskaya operation, but in the subsequent battles: Proskurovo-Tchernigovskaya and Umansko-Botochskaya operations. On the two regiments (11th and 72nd Independent Guards Heavy Tank Regiments) equipped with these tanks the most successful was the 72nd Regiment, especially during the period from 20 of April to 10 of May 1944.
During that period, the Regiment was incorporated to the 1st Guards Tank Army and took part in actions near Obertin (Ivano-Frankovsky region). After 20 days of non-stop fighting, they lost only eight JS-2s, the Regiment destroyed forty one Tiger I and Elephants/Ferdinands (this is according to some After Battle Report, but more likely there were StuGs, not Ferdinands) , 3 ammunition carriers and 10 anti-tank guns. The most significant information about JS-2 capabilities is given in a Tank Damage Report of that period:
"The 20 of April, tank No.40247 came under fire from a self-propelled gun "Ferdinand" from a range of 1500-2000 metres. The tank-crew could fire only one shot because of the faulty firing mechanism. Manoeuvring to get away from the fire of self-propelled gun, JS-122 received, without any damage, 5 hits on the frontal plate. Meanwhile another unseen "Ferdinand" approached from the flank at a distance of 600-700 metres and perforated close to the right side of the engine compartment with an armor-piercing round. The crew left the immobilized tank, which burnt suddenly.
Tank No.40255 received a direct hit by a 88 mm round of "Tiger" in the frontal lower plate at a the distance of 1000-1100 metres. Because of that, the left fuel tank was penetrated and the driver was wounded by a fragment of armour. The rest of the crew received light burns. The tank was burnt out.
After receiving three shots from the 88 mm Tiger's rounds on the nose from a distance of 1000-1500 metres, tank No.4032 was destroyed by fire from another Tiger some 400-500 metres away. An 88 mm armor-piercing round penetrated the sloped armor plate from the right side. First the shell-case charges ignited, and then the fuel. The crew left the tank and evacuated the driver to the rear.
After being holed by 88 mm round of a "Tiger", from the distance 400 metres, on the frontal armor; the tank No.4033 was towed to the to a repair facility for repair.
Tank No.40260 was burned out after receiving a 88 mm round from a "Tiger", which fired at the left side from the flank at a range of 500 metres. The round damaged the engine and the tank ignited. The commander and the driver were wounded.
Tank No.40244 received a hit from an 88 mm armor-piercing round fired by a "Tiger". The hit was received at the close range of 800-1000 metres in the right side of the hull. The driver died and the diesel fuel from damaged right fuel tank ignited. The tank was evacuated and blown up by sappers.
Tank No.40263 caught fire after two rounds hit its side.
Tank No.40273 was on its own, apart from the Regiment, and the 30 of April, near Iggisk, received two direct hits: the first in the turret and, immediately after, the second in the side plate of the engine compartment. The crew in the turret died at once, and the driver was wounded. The tank was left in enemy territory. During the combat, the tank crew participated in the repulse of the attack of 50 T-IIIs, T-IVs and T-VIs [the Russian term for Pz-III, Pz-IV, Pz-VI - Valeri P.] which were supported by artillery and air attacks.
Tank No.40254 was damaged from a distance of 800-1000 metres, by a "Ferdinand" in ambush. The first round did not penetrate the turret ring, but the second round put the engine out of order. The crew was evacuated and the tank was burnt out on the battle field.
Tank No.40261 received a direct hit into the gun barrel. After the combat the barrel was changed for a new one."
[Please note: although the Russians usually confused StuG to the Ferdinand, in this report Ferdinand was confused to the Marder. - Valeri P.]
Moreover, one tank was evacuated and taken away for rebuilding and the Regimental repair crew repaired other five damaged tanks.
From the middle to the end of May 1944, the Regiment was incorporated into the 18th Army, which participated in defensive actions against enemy counterattacks south-east of Stanislav.
From June 1944 to the end of the war, the Regiment was incorporated into the 4th Tank Army. The Regiment took part in the Lvov-Sandomirs, Nizhne-Silezskaya, Verkhne-Silezskaya, Berlin, and Prague offensive operations. For the liberation of Lvov, the Regiment was honored with the name "Lvovskiy". For military services during the war the Regiment was decorated with the Orders of Red Banner, Suvorov 3rd grade, Kutuzov 3rd grade, Bogdan Khmelnitsky 2nd grade and Alexander Nevsky.
Despite the fact that the career of 71st Independent Guards Heavy Tank Regiment, equipped with the JS-2s, was not so remarkable, it still deserves special attention. In August 1944, the Regiment, together with 6th Guards Tank Corps, participated in the defeat of Konig Tiger battalion on the Sandomirs bridgehead.
JS-2's and Tigers I and II engaged only occasionally. For example, in November 1944, there was a battle where several JS-2's were involved in close battle with German tanks of the 503rd PzAbt (near the Budapest, Hungary). A larger battle occurred on 12 January of 1945 during the Visla-Oder offensive operation: a column of Konig Tigers of the 524th PzAbt was involved in close combat with Soviet tanks near Lysov. Both sides suffered heavy losses.
It is important to remark that the Germans weren't able to access and analyze the JS-2 for quite a long time. That was because the Russians were in control of the battlefields. Such a case happened only in May of 1944 near the Rumanian town of Tigru-Frumos.
From December 1944, formation of new Independent Guards Heavy Tank Brigades was begun. Usually they were based on existing Tank Brigades which were equipped with the T-34-85. First of all, these new groups were formed to overcome well-prepared German defences and, in additional, for successful combat with German tank units.
According to the TO&E, each of the new Independent Guards Heavy Tank Brigade consisted of three heavy tank regiments, one motorised SMG infantry battalion, and support units such as signals, medical, etc. The total strength of an Independent Guards Heavy Tank Brigade was 1,665 men, sixty five JS-2 tanks, one light SP battery of three SU-76M, nineteen lend-lease M3 half-tracks and three armored cars. In total, five Independent Guards Heavy Tank Brigade were formed. Two of them - the 7th and 11th - took part in the Berlin Operation.
At the end of the war, each Tank Corps should have at least one Tank Regiment of JS-2 tanks, which were best for breaking through a heavily entrenched enemy line. A single 122 mm shot could penetrate the armored cupola of a concrete bunker, or shatter the main redbrick walls of the Konigsberg. At that time, an infantryman with a Faustpatrone, a Panzerfaust, or even a Panzerschreck, became the most dangerous enemy of the JS-2. Russians didn't distinguish these weapons and called them all "faust". Thus, an infantryman with a "faust" was called a "faustnik". During street fighting, about 70% of destroyed tanks were hit by "fausts".
From the beginning of 1945 Soviet tanks received shields of various designs. These shields were intended to protect from HEAT munitions (e.g. "fausts"). Most of these shields only protected turret, whilst hull remained unprotected. That was not so bad, as many people think now, because over 80% of "faust" hits were on the turret side. A shaped-charge round would completely destroy the shield, but leave the main armor unbreached, leaving a small black hole in it. Soviet tankers called such holes as "the kiss of the witch".
Unfortunately, these shields might be torn off by a shell, or explosion. The result could be fatal. Lieutenant-Colonel V.Mindlin (a participant of battles for Berlin) wrote in his memoirs "The Last Battle - the Hard Battle!" about this:
"Here is a tank with battened down hatches... but the crew is silent. They respond to neither radio nor knock. There is a small hole with a diameter no more than a cent. That was a "faust", that was its work. A shield was torn off, and a next round penetrated the armor...
Those who saw a tank battle knew how terrible death could be for tankers. If a round hit the ammunition or fuel tanks, a tank would be destroyed at once - just blast off and the crew perishing without any torture.
Often a round just penetrates the tank's armor but doesn't hit the ammunition or fuel tanks. All crewmembers are wounded, their tank is burning, but the crew is unable to extinguish the flame. They need to escape the tank and run off to a safe distance. However, the tankers are wounded and they simply can't do that, they can't open the locked hatches. And you can hear the cries of those being burned alive. You can't help them because the hatches are locked inside..."
It was very dangerous to fight with open hatches (and prohibited, by the way) because enemy infantry could throw a grenade into a tank. Thus, all crews received an order to close hatches but not to lock them. As a result the losses crew were reduced.
For better performance in street fighting, the Russians used a special formation called "elochka" (a fir-tree). A tank platoon (4 tanks) was divided into two pairs. The first pair moving on both sides of a street (the first tank on the left side, the second - on the right) in order to destroy any targets. This pair is covered by the second pair which moved towards them and protect them with additional gunfire until the first pair reload their guns.
Each tank company was supported by one infantry platoon. They protected their tanks from "faustniks". Additionally, special assault troops were formed. They consisted of one SMG platoon supported by a gun, usually a 76 mm regimental or divisional gun. Michael Badigin mentioned those troops in his memoirs.
DShK heavy machine-guns were very useful against enemy infantry. Unfortunately, they caught on tram-wires, so some crews dismounted these MGs before entering the cities.
Besides the Red Army, the JS-2 served in the Polish Army (Voisko Polskoe) - there were 71 tanks in the 4th and 5th Heavy Tank Regiments. During battles in Pomerania, the 4th Heavy Tank Regiment destroyed 31 enemy tanks and lost only 14 tanks.
Both regiments took part in the battle for Berlin. Poles planned to form another two regiments - 6th and 7th - but the war ended, so that plan was abandoned. At the end of the war, the Poles had 26 JS-2 heavy tanks; they returned 21 tanks to the Red Army. The remaining 5 tanks served in the Polish 7th Tank Regiment.
In the spring of 1945, just before the liberation of Prague, the Czech Army received several JS-2's.
In the beginning of the 1950's, several JS-2 heavy tanks were sent to China. According to some documents, during the Korean war, Chinese volunteers used them against the Americans. Unfortunately I was unable to verify this. American intelligence spotted at least four Chinese independent tank regiments. Each regiment consisted of four companies of T-34-85's and one company of JS-2's (five tanks).
During the war in Indo-China, French forces met with JS-2's which had been sent from China to Vietnam. A single ex-German Panther was sent to Vietnam for trials and to counter the JS-2 tanks, but it got mired in the jungle.
In the early 1960's, Cuba received two regiments of JS-2's. Some western sources say these tanks are still serving in the coastal defense system as pillboxes.
At the same time, some JS-2's were sent to North Korea. Two Korean tank divisions had one heavy tank regiment each.
In the Soviet Army, the JS-2M served for a very long time. They survived the later JS-3 and JS-4. They were supposed to be replaced with the T-10, but that did not happen. In the 1970's, they were used in the Far East fortified sectors as pillboxes.
The last time the JS-2M tank was used was in 1982 in the Odessa Military District during manoeuvres. However, the official order to remove the JS-2 from service was only issued in 1995! I doubt that an unsuccessful tank could serve for such a long time! All German tanks and projects were abandoned much earlier, it is important to keep in mind during the absurd (but still very popular) "best tank of..." debates.
JS-2 in Comparison to the German Counterparts
A comparison of the JS with German heavy tanks of WWII shows the big difference in design and war theories between the USSR and Germany. For example, according to the Soviet classification system, the JS-2 was a heavy tank, while the Panther was a medium tank according to the German classification system. In fact, both tanks were of equal weight. So why the difference of classification? Simply, because Soviet tank designers thought the weight of a vehicle to be the most important parameter by which to define most other parameters like engines, armor, armament, ammunition, fuel capacity, suspension and so on. At the same time, German designers distinguished tanks by their battle capabilities - mostly by armament and armoring. That's why Pz-IV's of the first series were considered "heavy", and Pz-IV's of later versions were designated as medium (even though heavier!) as was the 45-ton Panther. By the German system, the JS-2 would be a super-heavy tank (because of 122 mm Gun and a 12.7 mm HMG). So the German system seems to me awkward for comparing the tanks of different countries. Thus, I chose the Soviet classification system. If you wish, you may choose another system, but use the same system for all tanks. It is important to say, that in German production the tanks are divided into three classes: - leichte means light - mittlere schwere means medium heavy - uber schwere means super heavy (both Panther and Tiger belongs to this class) Thus, it's three classes as all other have, light, medium and heavy. It is a translations error to call JS-2 as a "super-heavy", because the Germans used their word for heavy (schwere) twice.
"Panther" as an Adversary of the JS-2
The weight of both tanks was the same. The JS-2 had better penetration ability, it could penetrate the Panther's frontal armor from 1100-1200 metres, while the Panther could penetrate the JS-2's armor from only 600-700 metres. In addition, the 122 mm gun had greater HE ability which is extremely important for combat with anti-tank guns and infantry (the weight of a 122 mm fragmentation shell was 25 kg, while the German - only 4.7 kg). One of the main drawbacks of the JS-2 was a small magazine - only 28 shells (the Panther had 81 rounds). The JS-2 had multi-part loading shots which slowed reloading and, as a result, resulted in a low rate of fire.
Today, most tank enthusiasts are interested in the AP ability of tank guns, forgetting the HE ability. However, that is ridiculous and stupid! The JS-2 was a heavy breakthrough tank, i.e. a tank intended for breaking through the enemy's lines of defense. In other words, the main targets of this tank were infantry and artillery. Thus, a tank with a large gun with great HE capability was needed. History showed that the JS-2 used about 70% of its HE ammunition and only 30% of its AP ammunition.
That is why the HE ability was considered more important.
Also, the JS-2 had much better armor protection than the Panther, but heavy armoring constrained by low weight dictated less internal space for the JS-2's crew and ammunition (this was the main reason for the small ammo magazine). Moreover, the Panther had better specific power - 15 hp/ton, while the JS-2 - only 11.3 hp/ton, which was also very important.
"Tiger" as an Adversary of the JS-2
Compared with the Tiger, the JS-2 was slightly better protected even though it was ten tons lighter.. The 88 mm and 122 mm guns had more or less the same AP ability, but again, German gun had less HE ability. Both tanks could penetrate each other's frontal armor from ~1000 metres. At greater distances success highly depended on experience of the crew and battle conditions.
The JS-2 had thicker armor, thus it had a better chance at distances over 1500 metres. On the other hand, the Tiger had better optics and thus had a better chance of hitting the JS-2. The main drawback of the Tiger was the slow angular velocity of the turret. However, the Tiger had an excellent length/width ratio (almost 1:1) which made it extremely maneuverable. And if the Tiger could not traverse its turret fast enough, the whole tank could swivel to bring the gun to bear.
"King Tiger" as an Adversary of the JS-2
In August 1944, new German tanks appeared on the Eastern Front: King (Koenig) Tigers. Weighing 68 tons, this tank was larger and much heavier than the JS-2.
The first engagement of Soviet tanks with King Tigers did not favor the Germans; on August 13 of 1944 a company of JS-2 tanks (the 3rd Battalion of the 71st Guards Heavy Tank Regiment) commanded 1st Lieutenant Klimenkov engaged in close combat with German tanks, knocked out one King Tiger and burnt another King Tiger. About at the same time, a single JS-2 of the 1st Lieutenant Udalov ambushed 7 King Tigers, knocked out one of them and burnt another one. Survived five German tanks attempted to retreat but Udalov made a maneuver and destroyed third King Tiger. Four other tanks flee in panic. Details of that battle are here.
Anyway, engagements between JS-2's and King Tigers were rare because the Germans seldom used them on the Eastern Front. On 12 November 1944, not far from Budapest, a skirmish occurred between JS-2's and King Tigers of the 503rd PzAbt. Both sides lost several tanks. On January 12, 1945, a column of King Tigers of the 524th PzAbt engaged in close combat with JS-2's (near Lisuv). In the fierce battle both sides had heavy losses.
It is not fair to compare the JS-2 and King Tiger because of the large disparity in weight - more than 20 tons! It would be better to classify the King Tiger as a super-heavy tank. It had thicker armor and its 88 KwK gun was slightly superior in AP ability, though inferior in HE ability.
Many times I noticed some individuals tried to compare armor penetration values of the 8,8-cm KwK 43 and the 122-mm D-25T. Unfortunately, these individuals paid no attention on different nature of those values: they were calculated by different methods. In short, the difference of calculation was about 25%. Therefore, it would be better to either increase Soviet figures on 25% or decrease German figures. Of course, the result would be very approximate, but it is much better then direct comparison.
The reliability of the King Tiger was poor, especially of first series, this is clearly stated in the follow report. The rate of fire of the King Tiger was definitely higher, ammo load was also larger. From the other side, the mobility of the JS-2 was much better. Further, the JS-2 was much cheaper than the King Tiger, which is also a very important consideration.
Sources: "The JS heavy tank", Manual, 1944; "Artillery armament for the Soviet tanks 1940-1945", Armada-Vertical No.4, 1999; "Report of the artillery tests of the armor protection of JS-85 and JS-122", NII-48, Sverdlovsk, 1944; "A short technical report about the improving the armoring of the JS", NII-48, Sverdlovsk, 1944; "Studying the JS tanks being destroyed in summer-autumn 1944", NII-48, Sverdlovsk, 1945; "From the experiense of usage a tanks during the Great Patriotic War. Part I", 1946; "Heavy tanks and SP guns in action", NKTP, 1945; "About the tactic of the heavy tanksand SP guns during the street fighting", Handbook, 1945; M.Svirin "The JS tanks" Armada No.6, 1998.