The Battle of Summa was fought between the Soviet Union and Finland. It was fought near the village of Summa along the main road leading from Leningrad to Viipuri. Combatants Finland Soviet Union Commanders Carl Gustaf Emil Mannerheim Kliment Voroshilov, later Semyon Timoshenko Strength 250,000 men 30 tanks 130 aircraft[1][2] 1,000,000 men 3,000 tanks 3,800 aircraft[3][4] Casualties 26,662 dead 39,886 wounded 1,000 captured[5] 126,875 dead... Combatants Finland Soviet Union Commanders Carl Gustaf Emil Mannerheim Kliment Voroshilov, later Semyon Timoshenko Strength 250,000 men 30 tanks 130 aircraft[1][2] 1,000,000 men 3,000 tanks 3,800 aircraft[3][4] Casualties 26,662 dead 39,886 wounded 1,000 captured[5] 126,875 dead... The Battle of Tolvajärvi [tolva,jærvi] was fought on December 12th in 1939 between Finnish and Soviet forces. ... Combatants Finland Soviet Union Commanders Colonel Hjalmar Siilasvuo General Dashitsev Strength Three regiments and separate battalions, 11,000 men Two divisions, one tank brigade (cca 45,000-50,000 men) Casualties 900 killed, 1770 wounded 27,500 killed and missing 85 tanks 537 trucks 1,620 horses 138 guns 6... Combatants Finland Soviet Union Commanders Hjalmar Siilasvuo Kombrig Vinogradov Strength 6,000 25,000 Casualties 900 killed 17,500 killed, wounded and missing 1200 captured The battle of Raate-Road was fought between Soviet Union and Finland in January, 1940 as a part of the battle of Suomussalmi. ... The Battle of Honkaniemi was fought between Finnish and Soviet forces on 26 February 1940. ... Combatants Finland Soviet Union Commanders general Hägglund colonel Svensson Strength 1 division and some small units 4 divisions, 1 tank brigade The Battle of Kollaa was fought on December 7, 1939 - March 13, 1940 in the Ladogas Karelia, Finland as a part of the Winter War. ... Combatants Finland Soviet Union Commanders Major General Kurt Martti Wallenius  ? Strength Several battalions Two divisions Casualties  ?  ? The Battle of Salla was fought between Finnish and Soviet troops near Salla in northern Finland during the Winter War. ... The Battle of Petsamo was fought between Finnish and Soviet troops in the area of Petsamo in the far north of Finland. ...

As the Soviets found it too difficult to breach the line at the Summa sector, they attacked 10 kms to the east in a sector known as Lähde. If they broke through here then they could encircle the Finns holding the Summa position. Timoschenko knew he could beat the Finnsin a battle of attrition. His plan was to wear them down and go for an all out blow.

First large probing actions were launched against the Finnish lines. For 11 days the line held in all positions. Then the Soviets went all out on the 11th.

On the 12th of February a minor breach in the Finnish lines in the Lahde sector led to disaster. By that time so many breaches had occurred in the Mannerheim Line that the report wasn't treated with enough seriousness. The following morning a counter-attack was supposed to be launched by the entire 5th Division, the only reserve in easy reach of the frontline, but only one of the three regiments was available as the other two regiments had to be parcelled out elsewhere.

In the end only two Battalions launched a counter-attack against two entire regiments well supplied with armour and artillery. The attack was thrown back with heavy Finnish casualties. The Russians made efforts to exploit the sailent. One tank Regiment made it as far as the Lahde road junction but halted. With total victory in their grasp the Russians halted their armoured spearhead.

Many Finnish companies were reduced to half their original strength. One company had lost 86 out 110 men. Over-night from the 14th to the 15th the Finns began withdrawing the Summa position. On the morning of the 15th the Russians attacked an empty position at Summa with more than 100 tanks and 2 divisions. That afternoon Mannerheim ordered a general retreat to the Intermediate Line