How the Red Army broke into the Mannerheim Line


Two soldiers of the Red Army with accordions on a blown up Finnish pillbox in the Summa-Hotinen area. 1940

Winter War. 80 years ago, on February 11, 1940, the troops of the North-Western Front under the command of S. K. Timoshenko began to break through the “Mannerheim Line”. Finnish concrete fortifications were destroyed with heavy artillery, explosives, flamethrowers and aerial bombs.

Work on bugs

The first time the Red Army did not manage to break through the line of defense of the Finnish army. At the same time, the beginning of the war against Finland was correctly chosen by the supreme Soviet command. The area in the Finnish direction was distinguished by numerous rivers, streams, lakes, swamps. In December, the soil was seized by frost, numerous reservoirs froze. But there was still little snow. That is, the Red Army could use its advantage in mechanization.

The Red Army could well have broken through the Mannerheim Line. The Finnish line of defense was far from perfect. Most of the permanent structures were one-story, partially buried reinforced concrete structures in the form of a bunker, which were divided into several rooms. Three Dotas of the “million” type had two levels, three more – three levels. The Finns did not have the underground galleries common for France, Germany and Czechoslovakia that connected the pillboxes. There were no underground narrow-gauge railways. The “Mannerheim Line”, in comparison with other similar lines of defense, had a lower density of pillboxes per kilometer, and was inferior in the number of artillery pillboxes. Finnish artillery pillboxes did not have weapons that could hit any Soviet tank of that time. That is, the “Mannerheim line” was not “impregnable”.

The main problem of the Red Army was the lack of intelligence about the Finnish fortifications. There was only fragmentary information about the “Mannerheim line”. As Marshal Shaposhnikov noted: “For us, such a depth of defense was a certain surprise.” In particular, there was no information about the late fortifications of 1938-1939. Another important factor of failure is the balance of power in the initial period of the war. Hacking the Finnish defense required a decisive superiority in manpower and equipment, but there was none. Chief of the General Staff of the Red Army Tymoshenko wrote that intelligence reported that the Finns would have up to 10 infantry divisions and 15 separate battalions. In fact, the Finns deployed much more, they planned to attack before the war started. The Finns deployed 16 divisions and a significant number of separate battalions. We started the war with 21 divisions. Thus, the Red Army did not have a decisive advantage at the beginning of the war. Already during the war we brought forces on the Finnish front to 45 divisions and ended the war with 58 divisions.

In December 1939, only five Soviet divisions of the 7th Army were sent to three enemy divisions in permanent fortifications on the Karelian Isthmus. And the standard ratio of attacking and defending forces in the direction of the main attack is 1: 3. Later, the ratio became 6: 9, which is also far from the norm. In terms of the number of battalions and troops, the picture is still obvious: 80 estimated Finnish battalions against 84 Soviet ones; 130 thousand Finns against 139 thousand Soviet soldiers. It is clear that the Red Army had a strong advantage in armored vehicles, aviation and artillery. But the infantry is not in vain “the queen of the fields.” In addition, Soviet divisions were not put into battle all at once. As a result, the forces of the sides on the Karelian Isthmus were approximately the same, but the Finns were sitting in long-term fortifications. And the Red Army did not have complete information about the pillboxes, and the experience of storming them. Hence the corresponding result.

The picture in the secondary directions, for example, in the interval between the Ladoga and Onega lakes, was similar. Five divisions of the 8th Army attacked here. These are 43 settlement battalions. On the Finnish side, two infantry divisions and a network of separate battalions were defended – these are 25 settlement battalions. That is, the ratio of forces is 1: 3 and not close. The same balance of forces was between the Finnish army and the Soviet troops allocated for the offensive. The Finns had 170 settlement battalions, the Red Army had 185 settlement battalions. It is obvious that the Soviet high command underestimated the enemy and did not provide a decisive superiority of forces at the beginning of the war. Errors were corrected already during the war.


Hero of the Soviet Union Lieutenant Mikhail Ivanovich Sipovich (left, in a destroyed observation hood) and Captain Ivan Evdokimovich Korovin at the captured Finnish bunker


Red Army soldiers cleaning a 203-mm B-4 howitzer on the Karelian Isthmus. February 1940


Soviet 203-mm B-4 howitzer in a firing position on the Karelian Isthmus. February 1940

Storming by all the rules

After it became obvious that the Finnish defense could not be broken on the move, strong fortifications in front of the Red Army and the Finnish military-political leadership put everyone they could put under arms, and even attracted foreign volunteers (the prospect of the arrival of the British and French on the front also appeared ), it was decided to storm the “Mannerheim Line” in accordance with all the rules of military art. The troops in the Karelian direction were significantly strengthened. From the troops of the right wing of the 7th Army, a new 13th Army was formed. The 7th army was brought up to 12 divisions, the 11th army – 9 divisions, 2 divisions were in the front reserve, 3 divisions – in the headquarters reserve. Artillery was built up.

As a result, the ratio of forces compared to December 1939 on February 12, 1940 began to correspond to the 1: 3 standard. The Red Army now numbered 460 thousand people against 150 thousand Finns. Soviet troops on the Karelian Isthmus now numbered 26 divisions, 1 rifle and machine gun and 7 tank brigades. The Finns had 7 infantry divisions, 1 infantry, 1 cavalry brigade, 10 separate infantry, jaeger and mobile regiments. There were 239 Soviet battalions for 80 Finnish battalions. Soviet troops had 10 times superiority in artillery with a caliber of 122 mm or more. Soviet troops had four divisions of high power to destroy reinforced concrete fortifications.

Thus, when the appropriate forces and means were accumulated to destroy the Finnish fortified areas, the Red Army broke into the “Mannerheim line”, despite the winter, snow and Finnish stubbornness. Bunkers and bunkers were destroyed by artillery of 152, 203 and 280-mm caliber. The 203-mm howitzer of the 1931 model (B-4) was nicknamed the “Stalinist sledgehammer” by Finnish soldiers, and ours called the “Karelian sculptor”, since they turned permanent structures into bizarre concrete and steel ruins (“Karelian monuments”). To destroy the pillbox required from 8 to 140 hundred-kilogram shells of these guns. At the same time, the pillbox usually lost its combat significance already at the beginning of the process. But only complete destruction convinced the infantry that they could move on.

For example, the 123rd Infantry Division of the 7th Soviet Army, which stormed Summayarvi, in February 1940 had 18 203-mm “Stalin’s sledgehammers” and 6 280-mm mortars “Br-2”. They used up 4419 shells during the preparation of the offensive in the first ten days of February, having achieved 247 direct hits. Dot “Popius”, which stopped the division in December 1939, was destroyed by 53 direct hits. Also, explosives were actively used to eliminate enemy fortifications. Thus, the second powerful fortification of the Summayarvi junction of bunker No. 0011 was blown up, laying a mountain of boxes with explosives on it. First, the artillery knocked out the Finnish infantry around the bunker, the Soviet riflemen completed this process, the sappers planted explosives. An explosion on the roof of the western casemate forced the Finnish garrison to flee. Then the pillbox was finished off with two tons of TNT, laid under the walls.

Also, quite usual means dealt with other engineering structures of the line. Nadolbs were blown up by explosive charges, moved by T-28 tanks, destroyed by armor-piercing shells. Passages in minefields and barbed wire were made by artillery and mortars. Severe frost and deep snow did not save the Finns.


Soviet tank T-28 on the march on the Karelian Isthmus. 1940


Soviet heavy tank T-100 from a special group of heavy tanks on the Karelian Isthmus. February 1940


Soviet chemical (flamethrower) tank HT-26 in action on the Karelian Isthmus. February 1940


Soviet tank BT-5 is firing at a Finnish bunker on the Karelian Isthmus. February 1940

Victory February 1940

On February 11, after a strong artillery barrage, a general offensive of the Red Army began. The main blow was struck on the Karelian Isthmus. After a three-day assault, the 7th Army divisions broke through the first line of defense of the line. Tanks were introduced into the breakthrough. The Finns, in order to avoid the encirclement, retreated to the second line of defense. By February 21, our troops reached the second line of defense, on March 13 they entered Vyborg. The defense was broken, the Finnish army was defeated, and further resistance was pointless. Finland had no choice but to ask for peace.

The stoppage of the Red Army in the Winter War was associated with errors of command and intelligence, underestimation of the enemy. It was necessary to work on the mistakes, accumulate forces and means and storm the “Mannerheim line” in accordance with all the rules of military art. After eliminating errors, accumulating forces, the Finnish defense was hacked at a good pace.

The Red Army has shown that there is no “impregnable” defense for a modern army. During the operational pause, the location of all enemy fortifications was found out. Concrete fortifications were destroyed with heavy artillery, explosives, flamethrowers, and aerial bombs. In addition, the Finnish army had weak artillery, aviation and tank units and could not provide effective resistance.

As a result, the Finnish campaign revealed both the shortcomings in the command of the Red Army and the capabilities of the Red Army as a completely modern army for 1940, mechanized, with a lot of artillery, tanks, aircraft, special and engineering units. The Soviet army could break through a strong enemy defense, develop success with a strike by tank formations and infantry.

True, the “world community” remained under the impression of the first stage of the war – unsuccessful for the Red Army. In January 1940, Churchill announced that Finland had “exposed the weakness of the Red Army to the whole world.” This erroneous opinion was shared by Hitler and his entourage, which led to fatal mistakes in the military-political strategy of the Reich in relation to the USSR.


A link of Soviet SB bombers in flight. February 1940


Residents of Leningrad greet the tankers of the 20th Tank Brigade in T-28 tanks returning from the Karelian Isthmus. 1940


Leningraders on the Liteiny Bridge meet a column of OT-130 tanks (a flamethrower tank based on the T-26 tank) returning from the Karelian Isthmus. March 30, 1940

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