General Waldemar Erfurth, the chief of the German liaison staff at Mannerheim’s headquarters, relates a completely different story from that told by Mannerheim:
As the Finns saw it, based on the experience of all former wars against Russia, the main theater of war had to be the Karelian Isthmus…. It was, therefore, quite natural that the thoughts of the Finnish Commander-in-Chief were occupied chiefly with the Karelian Isthmus as the main theater of war of the planned Finnish offensive. The deployment of Finnish forces was carried out mainly in accordance with this idea.5
Erfurth continues:
The German brothers-in-arms had other plans, however. The greater the success of the German offensive in western Russia, the more pressing became the demands of the German High Command that Marshal Mannerheim should not direct the main thrust of his army by way of the Karelian Isthmus toward Leningrad, but east of Lake Ladoga toward Lodeynoye Pole on the Svir. The German Army High Command desired that the strongest possible Finnish forces advance to the Svir and there unite for a decisive operation with Army Group North, which was proceeding across the Volkhov River.6
General Hermann Hölter, who was present in Finland at the time, supports Erfurth’s story. He writes:
During the first consideration of operations by the Finns, the Karelian Isthmus was instinctively in the foreground of strategic wishes. The wish of the German High Command, however, that the Finns should make their principal thrust east of Lake Ladoga, in order to “join hands” with the German Army Group on the Svir, led to the operations of the “Finnish Karelian Army” under General Heinrichs through Ladogan Karelia to the Svir.7
It is not clear why Mannerheim elected not to conduct simultaneous offensives on both sides of Lake Ladoga and across the Karelian Isthmus, or what the German views were on this issue. Mannerheim may have hoped that the German Army Group North’s continued drive towards Leningrad would cause the Soviets, in an effort to halt the German advance, to substantially reduce their forces on the isthmus. A delayed Finnish advance in this area would encounter less opposition. This appears to be what eventually happened. There may also have been logistical reasons for staggering the offensives.
It was important for the Finns to quickly occupy both Ladogan Karelia and the Karelian Isthmus. Soviet air attacks against Finnish towns presented a serious problem. Enemy bombers usually approached Finland across the Gulf of Finland from their airfields in Estonia. There was not much the Finns could do about this threat since their air force was too weak to prevent the raids. The Finns hoped that the advance of Army Group North would soon eliminate this threat.
The Soviets had expanded old airfields and built new ones in the territory they had conquered in the Winter War on the Karelian Isthmus and in the area east of Lake Ladoga. Soviet aircraft using these fields presented a difficult problem for the Finnish early warning network and their air defense forces. Since the removal of this threat could be accomplished only with Finnish ground offensives, their elimination played a prominent part in Finnish planning.
The Finnish forces were deployed generally along a line from Hanko on the Gulf of Finland to an area around Lieksa, southwest of Belomorsk (Sorokka). Along this line the Finns had deployed five army corps as follows:
1. IV Corps, commanded by Major General Karl Lennart Oesch, had its right wing on the Gulf of Finland west of Viipuri and its left wing on the Vuoksi River. It consisted initially of three divisions—8th, 12th and 4th—and the 2nd Coastal Brigade. The 10th Division was apparently in a reserve status to the rear of the boundary between IV Corps and II Corps.8
2. The II Corps, commanded by Major General Taavetti Laatikainen, occupied a front north of the Karelian Isthmus and Lake Ladoga stretching from the left flank of IV Corps to the right flank of VII Corps. It consisted initially of three divisions—the 2nd, 18th, and 15th.
3. The Army of Karelia occupied the front from the left flank of II Corps opposite the narrows between Lakes Pyha and Ladoga in the south to just north of Ilomantsi in the north. Under normal circumstances Finnish corps were directed by the Finnish High Command without the interposition of an army headquarters. An exception was made in this case as it appeared doubtful that a multi-corps advance into Karelia could be effectively directed from Mannerheim’s headquarters. The decision was made to create an army—the Army of Karelia—under the command of Lieutenant General Heinrichs, Mannerheim’s chief of staff. He retained his job as chief of staff but the duties were actually performed by deputies, first by Major General Viljo Einar Tuompo, chief of the command section and later by Major General Edvard Fritjof Hanell, chief of fortifications. The major units of the Army of Karelia were two corps, one light corps-size group, and an army reserve.
a. VII Corps, commanded by Major General Johan Woldemar Hägglund, occupied the right wing of the Army of Karelia, from Lake Pyha to the outskirts of Vyartsilya (Värtsilä). It consisted initially of two divisions—the 19th and 7th.
b. VI Corps held the center of the Army of Karelia from Vyartsilya to Korpiselkya (Korpiselkä). It was commanded by Major General Paavo Juho Talvela and consisted initially of the 11th and 5th Divisions.
c. Task Force Oinonen occupied the left wing of the Army of Karelia, positioned north of the Ilomantsi area. It consisted of the cavalry brigade and the 1st and 2nd Jäger Brigades.9 The task force was commanded by Major General Woldemar Oinonen.
d. The 1st Division was in reserve behind the Army of Karelia.
4. The 14th Division covered the left flank of the Finnish Army and filled the gap between that army and the Army of Norway. It was commanded by Colonel Erkki Johannes Raappana and stationed in the Lieksa area. This division was directly subordinated to Marshal Mannerheim.
5. The 17th Division had the mission of sealing off Hanko.
6. The 163rd German Infantry Division (minus one regiment) arrived in early July and Mannerheim stationed it initially at Joensuu behind the Army of Karelia as his reserve.10
The composition of the corps changed frequently during the war as corps headquarters were moved around and divisions and brigades were detached from one corps and attached to another.
The Soviet forces facing the Finnish Army were part of Marshal Klimenti Voroshilov’s Northwest Front. The 32nd Soviet Army11 was responsible for the area north of Lake Onega. It consisted of five divisions. In the Army of Karelia sector north and east of Lake Ladoga the Soviet 7th Army had three divisions forward and one in reserve. The Soviet 23rd Army on the Karelian Isthmus had four divisions of stationary troops manning the border fortifications and three divisions in reserve. The Soviet troops at Hanko consisted of two infantry brigades plus a number of specialized units. At the outset of the war the Soviets had the equivalent of 18 divisions at the fronts in Finland and they faced 15 Finnish and four German divisions.12
German pressure from the south forced the Soviets to weaken their forces along the Finnish border in order to make units available to contest the advance of Army Group North. By the time the Finns began their operations, the Soviets had redeployed nearly all their reserve formations. The Finns were thus confronted by only seven divisions plus the two brigades at Hanko, giving them a 4:1 superiority in infantry and a 9:1 superiority in artillery.13 They could also remain relatively assured that the forces opposing them would not increase markedly in the near future as the Soviets were throwing all they had at the approaching Germans.