As a small country, Finland knew that it could not stand alone against a single great power, and its vision of future war was that "if Finland were unfortunate enough to be drawn into a war involving a great power, Finland could count on assistance from the enemy side of the great power attacking Finland". The Finnish military authorities, Jihua, relied on the Mannerheim Line to contain and deplete the Soviet troops, and after obtaining foreign aid, they carried out counterattacks and tried to negotiate peace with the former Soviet Union under favorable conditions.

After rejecting the unreasonable demands of the Soviet Union, Finland estimated that the Soviet Union might invade on a large scale, so it began a national mobilization in advance, evacuated the population on the Karelian Isthmus, cleared the wilderness, and prepared for a long-term war of resistance.

By the beginning of the war, the Finnish Army had grown to more than 150,000 men, with 300,000 reservists, 100,000 reserve "National Guards" and 100,000 women's service corps. However, the Finnish army was very short of anti-tank guns and ammunition and fuel, and the whole army only had about 100 anti-tank guns, and the guns and ammunition were only enough for two months and the artillery shells were only enough for three weeks of combat. The Air Force is also insufficient, with only 30 bombers, 56 fighters, and 59 reconnaissance aircraft, and they are of older models.

However, Finland was united in its determination to resist the enemy, and even most of the members of the Finnish Communist Party sided with their own government and took up arms to fight against the Soviet Union, becoming the second red organization after China in which national feelings prevailed over ideology. However, this is also because some Finnish communists were suppressed by the intensifying "Great Purge" in the Soviet Union after they went to the Soviet Union, which increased the Finnish Communist Party's distrust of the Soviet Union; In addition, Finland has established a clean and efficient government after independence. Not only has the economy developed at a high speed, but the differences between various social classes have also been markedly narrowed, thus alleviating social contradictions and winning the universal support of the people in China.

In addition, the Soviet-Finnish border is sparsely populated, densely forested, crisscrossed by lakes, and inaccessible. However, the deep part of the Finnish border has a well-developed road network, with several railways running parallel to the border, which is convenient for the transportation of materials and the mobility of troops. And the Karelia region on the Soviet side is an uninhabited desert. From Leningrad to Murmansk there is only one railway parallel to the border and two branch lines to the border. In addition, the Soviet army far surpassed the Finnish army in terms of numbers and heavy equipment. Therefore, in terms of logistics and supply, the Finnish army has a clear advantage. Therefore, although he was afraid of the great power of the Soviet Union, the commander-in-chief of the Finnish army, the legendary Karl Brown. Gustav. Mannerheim was still confident that he could win the Great Patriotic War.

After the outbreak of the war, the combat operations of both sides were mainly concentrated in four areas of the border, namely the Karelian Isthmus, the northeastern part of Lake Ladoga, the middle of the border, and the area of Bessamou (now known as Bezinga). Among them, the strategically important Karelian Isthmus was the main target of the Soviet Union in launching this war. The traffic conditions here are better. There are 4 single-track railways and 10 stone roads. It has access to northwestern Finland.

The isthmus is about 100 kilometers wide, and the terrain is undulating, allowing vehicles to pass. However, it lacks a commanding height that is convenient for long-distance observation. The Vuoksa River runs through it, with abundant water and many deep lakes. Vyborg is the only small industrial city in the region and is the gateway to the Soviet-Finnish border. The Finnish Mannerheim Line, on the other hand, is an artificial barrier on the Karelian Isthmus, the focus of the Soviet offensive, and the hardest nut to crack.

After 10 years of painstaking operation in Finland, the Mannerheim Line has formed a complete system of fortifications. It consists of three defensive zones with a depth of about 90 km. Relying on natural obstacles such as swamps and lakes, each defense zone has 670 permanent firing fortifications and earth-wood firepower points, as well as nearly 800 underground bunkers, which are communicated by trenches and communication trenches. In front of the main defense zone, there is a support zone with a depth of 20~60 kilometers. Anti-tank and anti-infantry mines, anti-tank piles, anti-tank trenches and anti-tank cliffs are widely set up in front of the main defensive zone and in the support zone.

Historically, the Soviet army suffered extremely heavy losses on this defensive line, but in this time and space, because it had sent people to observe the battle of the People's Liberation Army to conquer the fortress group of the Japanese Kwantung Army, the Soviet Union sent B4 heavy howitzers with a caliber of 203 mm to the front line early, and under the cover of the aviation unit and the T34 tank group, they approached the target for direct artillery bombardment, and achieved good results, and countless Finnish troops did not even kill a single enemy, but died in the collapsed fortress. The Finns' defenses, which they thought were impregnable, were almost easily broken through by the Soviets.

The losses of the Soviet army were only more than 100 planes (including those that were wounded but could not be repaired) and a slightly larger number of tanks, which was completely insignificant to the Soviet Union, which now has tens of thousands of combat aircraft and tens of thousands of tanks. And it's not just this battlefield that's so different from the historical wars

In the northeastern part of Lake Ladoga, there is an approach road that bypasses the northern shore of Lake Ladoga to the southern part of the Karelian Isthmus, but it is far away and there is a narrow pass between Lake Saimaa and Lake Ladoga, which is easily blocked and truncated by the defenders. The Soviet 8th Army, which had just become the second tank army of the Soviet Union half a year ago, had two tank corps and one mechanized corps (mechanized infantry) under its jurisdiction, with more than 800 tanks, armored vehicles and self-propelled guns.

In the face of the Soviet army's armored clusters, although the three infantry divisions of the Finnish army were blocked with the cooperation of the guerrillas, they were diametrically opposed to the historical war that was fought in winter, and because of the location in the cold zone, the night was extremely long, so that the Soviet army's air superiority could not be brought into play at all, and now it is late spring when the days are long and the nights are short, which makes the Soviet bombers like fish in water and gives the Finnish army a great blow. The anti-tank trenches and other field fortifications dug by the Finnish army before the war did not play a big role because the Soviet 8th Army had tens of thousands of mechanized infantry.

It is worth mentioning that although the combat effectiveness of the infantry of the Soviet army has dropped very much due to the "Great Purge", the extensive equipment of new automatic weapons such as AKM automatic rifles has increased their firepower by more than ten times, so their actual combat power is not inferior to that of the Finnish army.

After the front line position was torn open by the Soviet infantry and tank coordination, the power of the armored torrent was immediately revealed, and seven or eight hundred tanks and armored vehicles drove straight in, and with the cooperation of the huge Soviet aircraft group, the Finnish troops in the rear were suddenly rushed. Although the Finnish army fought valiantly, it still suffered most casualties in just two or three days, and many troops did not even retreat, suffering the worst defeat on all fronts (to be continued......