The Winter War - Aftermath
Analysis
Before peace had been signed, Stavka was already working on analysing the bitter victory over a minor nation. All estimates had predicted a walkover, but the month of combat in which soviet troops took great casualities, quickly showed otherwise. It was imperative to scrutinize every aspect of the war to mend the shortcomings that were now apparently there. All major commanders (Shaposnikov as the head of Stavka at the time, Kliment Voroshilov as the commander of the Red Army, Ivan Konev as the commander of the 1st Mechanized Army, Semyon Timoshenko as the commander of the Leningrad Front, Valerian Frolov as the commander of the Karelian Front) of the war were to start working on detailed reports on the war. Only the Karelian Front had performed as was expected from them, and the reason for that was mainly small finnish troop presence in their area.
Most important was the study of the first battle of the Mannerheim line, in which the much vaunted mechanized army was defeated in a brutal 8 day battle. The first reason that was cited by all participants was: "...terrible co-operation [...] lack of communications between advancing and supporting units, and their tactical reserves [...] headlessness on polk level and lower eventually resulted in the attack running out of steam and into a disorganized mess over which the division and corps commanders had no control" (Ivan Konev, from the monograph "Study of mechanized elements in the Soviet-Finnish war"). Timoshenko arrived at the same conclusion, although shifting much of the blame unto supporting branches: "The first artillery strike on the first day of the war, the 15th, was largely ineffectual due to poor aerial scouting and lack of scout formations in the artillery formations, as well as the lack of communication between Kuznetsov's fleet (and its huge 450 mm guns of the battleships) and the land forces, often resulting in the naval gunfire ending up completely off-target." (Semyon Timoshenko, from the monograph "Critisisms on the Red Army in 1939"). Timoshenkos accusal of the naval elements can however be seen as an effort to clear his own units from blame, as the Leningrad Fleet was nearly impervious to critisism from anyone but Stalin himself. Indeed, the fleet didn't respond to these allegations at all, neither did it conduct an analysis of its combat performance. He also claimed: "The mechanized formations had no desire to wait up for their supporting units, and their own infantry support was too few and too motorized to function properly on the frozen and hostile terrain [...] A good example of communication error happened two days (20th) into the attack: when the first units of the Leningrad front advanced over the first line in the finnish defenses (the first light defense line, meant for delaying the advance units), now completely abandoned by finnish troops, they found interesting reports of the state of the finnish formations a day before. The most interesting fact in those documents was the situation of the finnish 18th division, which was apparently very undermanned, underequipped and demoralized from the first soviet armored offensive. However, these documents reached Stavka only on the 23rd, the day on which the attack was called off completely. Had that info been available to Stavka, or Konev, on the same day, the weakness of the 18th division could've been exploited easily, especially so because our intel had already identified the division as being in the complete center of the finnish defense line, a situation very suitable for our attack."
However, while Timoshenko's report focused mainly on the problems with communication and co-operation between different branches and formations, Konev also added: "... lack of force concentration from the Leningrad Front [...] lead to poor follow up assaults by supporting elements, leaving the breaching tanks alone and vulnerable." In his view, the decision to split up the infantry units of the Leningrad Front was a major cause of the defeat on the Mannerheim line, and in hindsight, the claim has some validity to it. The attacks north of lake Ladoga failed even with 3:1 superiority in numbers, making the 9 divisions that were allocated to the area completely useless for the rest of the war, as well as being another nail in the coffin of the first draft of the attack plan. Perhaps the deployement of the minimum necessary troops to north of Ladoga would've been a better course of action, leaving more troops free for the massive attack on the Mannerheim line. However, Konev expressed no such doubts prior to the assault, although later he, as well as Frolov, thought of this as the main error in the first battle plan.
All cited inadequate aerial support as a reason contributing to the defeat as well. Timoshenko: "...Rychagov (Chief of the Air Force) did not allocate it's scarce resources as necessary. The 1st CAS Fleet was stationed at Murmansk, where it played no effect in the combat at all. When redeployed southwards after the breakthrough of Frolov, they were ready for battle only by the last offensive to the Mannerheim line, on the 4th of December, that is, 19 days after the start of hostilities [...] Over half our aerial support resources entered the war near the end of the war". Seeing the effect of the air force during the second attack on the Mannerheim line, this claim seems to hold water. However, Timoshenko and Konev, as well as Stavka, had all the opportunities to demand the bombers be placed to the southern theatre. They did not do so, as pre-war estimates predicted hardships in the northern sector, despite Frolov assuring Stavka that the resources already allocated to him were enough to accomplish his objectives.
Konev's report also deals specifically with the problems of the armoured units as well. In his view, the decision to attach BA-20 brigades instead of KV-1 brigades "... was a total disaster [...] The armoured car formations had served us well against the japanese (referring to the battle of Khalkin-Gol earlier in the year) when the terrain was flat and spacious. But in the forests of Finland, the roadbound lightly armored cars could not support the advancing armour as was hoped, and their ability to suppress infantry with their machine guns was insignificant". Indeed, the BA-20 was designed as a infntry support vehicle meant for mopping up demoralized troops, but using them in parallel with the BT-5s and T-28s was a costly mistake. The KV-1 was a phenomenal tank that could've served the needs of the 1st Mechanized Army, and nearly a thousand of them were already produced, formed into 15 brigades in armies stationed in West Ukraine (occupied Poland). Not a single KV-1 saw combat in Finland, however.
Only Frolov's report had positive deductions in it. His monograph "Northern theatre of the Finnish war", focused on the exploits of the elite mountaineer troops under his command: "... most importantly, they were not confined to roads and railroads during offensives. Their attacks were mostly on foot, and they were transported via large transport hubs only when the situation demanded, like the quick dash towards Oulu, during which our armored trains, overcoming the difference of track width in Finland and Russia, proved themselves as an useful tool for rapid troop movement". He also claims: "... the mountaineer corps were most prepared for the war. It seemed like they were the only ones to understand that the combat would take place in winter, and indeed their history in the Caucasus and other mountainous regions made them well suited for winter warfare. But their light and mobile weaponry also helped their advances". This conclusion had little impact in Stavka, however, as light and mobile infantry was considered a novelty rather than a solution, and with good reason. While the mountaineers worked perfectly in hostile weather and terrain, the Soviet Union was a humongous nation with much more borders in mild climate rather than the extreme conditions of Lapland. Frolov would remain the commander of the Karelian Front, and was greatly rewarded for his results. It was also implied that in the future, he would be in charge of all operations against Finland, as well as devising them.
Doctrinal changes
The Red Army was already developing the "Deep Battle" doctrine (despite its connection to purged officers), of which Finland was hoped to be a good example of. The experience gained from the Winter War were instrumental in developing this school of thought. Combined arms was considered an easy feat to achieve earlier, but the poor communications showed how vulnerable different branches really were. Most important was the development and production of tank-level radios, which was considered a key aspect of a proper coordinated armoured offensive. This would be combined with lower-level command units, while still centralized to the Corps/Army command, effectively creating a third dimension next to strategy and tactics. This operational level would combine strategic goals and tactical means, hopefully resulting in a very flexible course of battle. It was an unorthodox plan, but very promising. Finland was not a site to test this doctrine though, and practical use would have to wait.
A very crucial reform after the war was the reduction of importance of the political comissars. The Red Army would be remodeled to be less politicized, and more like a convectional, traditional army. Commissars, while still a menacing force amongst officers, would no longer have the say in tactical and strategic decisions, leaving them the role of what was essentialy military police. Stalin saw the necessity of this, but compensated by meddling more with the decisions of Stavka in the future. However, this reform was a major step towards building up a proper, formidable fighting force.