Battles at the Interim Line in 1940
Soon after fighting broke out at the Interim Line, Soviet forces broke through to the Finnish positions at Näykkijärvi. The battles at the Interim Line lasted for more than ten days. During this time, Finnish forces also abandoned the Koivisto Islands and the southern shore of Vyborg Bay. The withdrawal to the Rear Line started on 27 February.
Edited map from the work Raunio, Ari, Sotatoimet – Suomen sotien 1939−45 kulku kartoin (Military Operations – The Course of Finnish Wars in 1939–45 with Maps). 3rd edition, Karttakeskus 2013.
The Koivisto (Beryozovye) Islands had to be held for the time being
The decision made by the commander-in-chief on 15 February regarding the Finnish forces’ withdrawal from the Mannerheim Line included the requirement that the Koivisto Islands be held. The reason for this was that the Saarenpää (Krasnoostrovskiy) Fort of the Koivisto (Bolshoy Beryozovy) Island’s coastal artillery had to maintain its capability to provide support fire for the infantry troops fighting at the Interim Line. The requirement that the Koivisto Islands be held changed the planned alignment of the Interim Line. The southern shore of Vyborg Bay was incorporated into the Interim Line.
Five divisions were deployed at the Interim Line
According to the II Corps’ (II C) retreat order, four of the divisions (2nd D, 1st D, 5th D and 4th D) under the army corps’ command at the time were to retreat to the Interim Line, while the fifth (3rd D) was to assemble as the commander-in-chief’s reserve in the Viipuri (Vyborg) area. As a replacement, the army corps received a division (23rd D) that had been transferred to the field army from the Home Troops in January. It had initially been concentrated in the area north of Lake Ladoga before being relocated to the Isthmus.
The transfer of this division (23rd D), which was commanded by Jaeger Officer, Colonel Gunnar Heinrichs and which had been called to service from the reserve, took so long that fighting had already commenced at the Interim Line by the time it arrived there. On 22 February, the division assumed responsibility for the front in the Näykkijärvi area, where the enemy had already broken through to the Finnish positions. Fighting had already broken out at the Interim Line while the troops were taking their positions.
On 22 February, the forces on the Koivisto Islands were given permission to leave the islands
On the evening of 17 February, an infantry regiment from the 4th Division (4th D), deployed between Humaljoki (Yermilovo) and Makslahti (Glebychevo), was subordinated to the Viipuri sector. The sector relocated the new infantry regiment to the Koivisto Islands the following day. On 22 February, the commander of the Army of the Isthmus gave the Viipuri sector’s forces permission to withdraw from the Koivisto Islands. The enemy’s attacks forced the troops under the Viipuri sector to withdraw from most of Pulliniemi (Moryakovo) and a part of the Uuras (Vysotsk) Islands.
Erik Heinrichs became commander of the Army of the Isthmus
On 19 February, the commander-in-chief appointed Major General Erik Heinrichs as the new commander of the Army of the Isthmus. He was promoted to Lieutenant General the same day. Lieutenant General Österman had requested to resign from his position, citing health reasons. According to him, he cited health reasons because he had considered the commander-in-chief’s decision to make the Interim Line into the new main defensive line to be a mistake.
Mannerheim ordered the commander of Group T, Jaeger Officer, Major General Paavo Talvela, to succeed Heinrichs as the commander of the III Corps. Mannerheim had promoted him to major general after the victory his forces had achieved in Tolvajärvi (Tolvoyarvi) in December.
Establishment of the I Corps
On 19 February, the commander-in-chief ordered the establishment of a new army corps. The 1st and 2nd Divisions of the II Corps were formed into the I Corps. Jaeger Major General Taavetti Laatikainen, the commander of the 1st Division, was appointed its commander. He was succeeded by Jaeger Officer, Colonel A. E. Martola, who had served as chief of staff at the Home Troops Headquarters.
The shortage of officers delayed the launching of the operations of the army corps, which had been formed from the divisions of the Central Karelian Isthmus. Laatikainen did not assume command of the divisions and responsibility for the front until 24 February.
Öhquist proposed withdrawing from the Interim Line on 21 February
The commander of the II Corps, Lieutenant General Harald Öhquist, proposed to the commander of the Army of the Isthmus on 21 February that the troops be pulled back to the Rear Line between Viipuri and Kuparsaari (Zhdanovsky Island). Heinrichs informed Öhquist that the troops had to hold the Interim Line for three to four weeks in order for the fortification of the Rear Line to be completed. Öhquist repeated his proposal the following day. In the late afternoon of 23 February, the Army of the Isthmus issued a preparatory order for the troops to withdraw from the Interim Line to the Rear Line.
Oinonen replaced Gunnar Heinrichs as division commander
Öhquist proposed to Erik Heinrichs that the commander of the 23rd Division be replaced. The commander to be replaced was Erik’s brother, Gunnar Heinrichs. Erik Heinrichs called Öhquist at midnight on 23 February to tell him that the commander-in-chief had accepted his proposal regarding the replacement of the commander of the 23rd Division. In accordance with Öhquist’s proposal, the commander-in-chief assigned Jaeger Officer, Colonel Woldemar Oinonen as the division’s new commander.
The Red Army transferred a new army corps to the front for deployment in Vyborg Bay
The new troops assigned to the Northwestern Front by the Main Command of the Red Army were formed into a rifle corps (28th RC), which was moved across the frozen Gulf of Finland to the Karelian Isthmus from 22 February onwards. Preparations were made to use the army corps for an offensive across Vyborg Bay.
The Northwestern Front prepared for a two-sided encirclement attack
With the Stavka’s permission, the Northwestern Front gave two extra days of rest to the troops of the 7th Army, which had advanced to the front of the new Finnish defensive positions at the Interim Line.
The attack on the Interim Line by the Northwestern Front involved the goal of destroying the Finnish forces stationed in the Viipuri area with a two-sided encirclement attack. The attack on the
left side was planned to be carried out as an offensive across the frozen Vyborg Bay, with the attack on the right side coming from east of Viipuri. One army (7th A) bore the main responsibility for the encirclement attack. The second army (13th A) at the front was to support the encirclement by attacking Antrea (Kamennogorsk). In the first phase of the plan, the 7th Army was to break through the Finnish defensive positions. The breakthrough attack was to be launched on 28 February.
The Finns started their retreat prior to the Soviet attack
Immediately after midnight on 27 February, the Army of the Isthmus ordered the army corps on the western Karelian Isthmus to withdraw to the Rear Line. The withdrawal was to start at nightfall on 27 February.
The 3rd Division, which was commanded by Jaeger Officer, Colonel Paavo Paalu and which had been the commander-in-chief’s reserve in the Viipuri area, was ordered on 27 February to assume responsibility for Viipuri’s defence and to receive troops detaching themselves from the Interim Line.
As a consequence of the withdrawal of Öhquist’s army corps (II C) and Laatikainen’s army corps (I C), the front line defended by Talvela’s army corps (III C) at the Vuoksi (Vuoksa) River expanded to cover the Äyräpää (Baryshevo)–Vuosalmi area. The 2nd Division (2nd D), which had previously belonged to Laatikainen’s army corps (I C), was subordinated to Talvela’s army corps. The I Corps was subsequently left under the command of one division (1st D) and Group Sihvo. The latter was a reinforced brigade, commanded by Jaeger Officer, Colonel Jussi Sihvo.