Editing Winter War (section)

===First battles and Soviet advance to Mannerheim Line===
[[File:Winterwar-december1939-karelianisthmus.png|thumb|alt=Diagram of the Karelian Isthmus, next to Leningrad, illustrates the positions of the Soviet and Finnish troops early in the war. The Red Army penetrated around 25 to 50 kilometres into Finnish territory on the Isthmus, but was stopped at the defensive Mannerheim Line.|The situation on 7 December: Soviets have reached the [[Mannerheim Line]] on the [[Karelian Isthmus]].{{legend|blue|Finnish division (XX) or corps (XXX)}}{{legend|red|Soviet division (XX), corps (XXX) or army (XXXX)}}]]

The array of Finnish defence structures that during the war started to be called the Mannerheim Line was located on the Karelian Isthmus approximately {{convert|30|to|75|km|mi|abbr=on}} from the Soviet border. The Red Army soldiers on the Isthmus numbered 250,000, facing 130,000 Finns.<ref name="UittoGeust8">[[#GeustUitto2006|Geust; Uitto (2006)]], p. 54</ref> The Finnish command deployed a [[defence in depth]] of about 21,000 men in the area in front of the Mannerheim Line to delay and damage the Red Army before it reached the line.<ref name="Trotter_69">[[#Trotter2002|Trotter (2002)]], p. 69</ref> In combat, the most severe cause of confusion among Finnish soldiers was Soviet tanks. The Finns had few [[anti-tank weapon]]s and insufficient training in modern [[Anti-tank warfare|anti-tank tactics]]. According to Trotter, the favoured Soviet armoured tactic was a simple frontal charge, the weaknesses of which could be exploited. The Finns learned that at close range, tanks could be dealt with in many ways; for example, logs and crowbars jammed into the [[Bogie#Tracked vehicles|bogie wheels]] would often immobilise a tank. Soon, Finns fielded a better ad hoc weapon, the [[Molotov cocktail]], a glass bottle filled with [[Flammability|flammable]] liquids and with a simple hand-lit [[Fuse (explosives)|fuse]]. Molotov cocktails were eventually mass-produced by the Finnish ''[[Alko]]'' alcoholic-beverage corporation and bundled with matches with which to light them. 80 Soviet tanks were destroyed in the border zone engagements.<ref name="Trotter_72-73">[[#Trotter2002|Trotter (2002)]], pp. 72–73</ref>

By 6 December, all of the Finnish covering forces had withdrawn to the Mannerheim Line. The Red Army began its first major attack against the Line in [[Solovyovo, Priozersky District, Leningrad Oblast|Taipale]]{{snd}}the area between the shore of Lake Ladoga, the [[Burnaya River|Taipale river]] and the [[Lake Sukhodolskoye|Suvanto]] waterway. Along the Suvanto sector, the Finns had a slight advantage of elevation and dry ground to dig into. The Finnish [[artillery]] had scouted the area and made fire plans in advance, anticipating a Soviet assault. The [[Battle of Taipale]] began with a forty-hour Soviet artillery preparation. After the [[Barrage (artillery)|barrage]], Soviet infantry attacked across open ground but was repulsed with heavy casualties. From 6 to 12 December, the Red Army continued to try to engage using only a single division. Next, the Red Army strengthened its artillery and deployed tanks and the [[150th Rifle Division (Russia)|150th Rifle Division]] forward to the Taipale front. On 14 December, the bolstered Soviet forces launched a new attack but were pushed back again. A third Soviet division entered the fight but performed poorly and panicked under shell fire. The assaults continued without success, and the Red Army suffered heavy losses. One typical Soviet attack during the battle lasted just an hour but left 1,000 dead and 27 tanks strewn on the ice.<ref name="Trotter_76-78">[[#Trotter2002|Trotter (2002)]], pp. 76–78</ref> North of Lake Ladoga on the [[Ladoga Karelia]] front, the defending Finnish units relied on the terrain. Ladoga Karelia, a large forest wilderness, did not have road networks for the modern Red Army.<ref name="Trotter_51-55">[[#Trotter2002|Trotter (2002)]], pp. 51–55</ref> The [[8th Army (Soviet Union)|Soviet 8th Army]] had extended a new railroad line to the border, which could double the supply capability on the front. On 12 December, the advancing Soviet [[139th Rifle Division]], supported by the [[56th Rifle Division (Soviet Union)|56th Rifle Division]], was defeated by a much smaller Finnish force under [[Paavo Talvela]] in [[Battle of Tolvajärvi|Tolvajärvi]], the first Finnish victory of the war.<ref name="Trotter_121">[[#Trotter2002|Trotter (2002)]], p. 121</ref>

In Central and Northern Finland, roads were few and the terrain hostile. The Finns did not expect large-scale Soviet attacks, but the Soviets sent eight divisions, heavily supported by armour and artillery. The [[155th Rifle Division (Soviet Union)|155th Rifle Division]] attacked at [[Battle of Ilomantsi (1939)|Ilomantsi]] and [[Lieksa]], and further north the [[44th Rifle Division (Soviet Union)|44th]] attacked at [[Battle of Kuhmo|Kuhmo]]. The 163rd Rifle Division was deployed at [[Suomussalmi]] and ordered to cut Finland in half by advancing on Raate road. In [[Finnish Lapland]], the Soviet [[88th Rifle Division (Soviet Union)|88th]] and 122nd Rifle Divisions attacked at [[Battle of Salla (1939)|Salla]]. The Arctic port of Petsamo was attacked by the 104th Mountain Rifle Division by sea and land, supported by [[Naval gunfire support|naval gunfire]].<ref name="Trotter_53-54">[[#Trotter2002|Trotter (2002)]], pp. 53–54</ref>