The 'Battle of Vuosalmi', which is also known as the 'Battle of Äyräpää-Vuosalmi', was fought between Soviet and Finnish forces within the context of the 'Jatkosota' continuation war (4/17 July 1944).
During the 'Vyborg-Petrozavodsk Strategic Offensive Operation', after they had come to appreciate that they had failed in the 'Battle of Tali-Ihantala' against the Finnish defenders late in June and early in July 1944, the Soviets tried to break the Finnish positions at Vuosalmi and encircle the southern part of the Finnish forces on the Karelian isthmus. General Major Aleksandr I. Cherepanov’s 23rd Army, of Marshal Sovetskogo Soyuza Leonid A. Govorov’s Leningrad Front had made unsuccessful small-scale attacks against the Finnish defences for nearly two weeks in the area of Äyräpää, but the 23rd Army’s lack of overall success led to a change of command on July 3, Cherepanov being replaced by General Leytenant Vasili I. Shvetsov.
The Finnish defences in the Vuosalmi sector initially comprised only Kenraalimajuri Armas-Eino Martola’s (from 6 July Kenraalimajuri Aarne Blick’s) 2nd Divisioona, but this was later reinforced, after the fighting in the Tali-Ihantala region had began to decline, by Eversti Yrjö Valkama’s 57th Jalkaväkirykmentti (infantry regiment) and the 25th Erillinen Pataljoona (separate battalion) of Eversti Niilo Hersalo’s 15th Divisioona, by the 4th Pataljoona of Eversti Lauri Maskula’s 19th Prikaata (brigade) and by parts of Kenraalimajuri Ernst Ruben Lagus’s Panssaridivisioona (armoured division) in the form of its assault gun battalion and four Jäger battalions. The Finnish infantry had the support of 21 battalions of artillery during critical last stage of the battle. On a proportional basis, the Finnish infantry battalions had greater artillery support in the 'Battle of Vuosalmi' than in the 'Battle of Tali-Ihantala'.
Under the command of Kenraalimajuri Hjalmar Siilasvuo’s III Armeijakunta (corps), the Finns could thus muster two infantry divisions, oner armoured division, one infantry brigade, one infantry regiment, one infantry battalion and four light infantry battalions. The number of men at the start of the battle was in the order of 20,000 men increasing to about 32,000 men by the middle of July. The average strength of the infantry division was about 13,300 men, of the infantry brigade some 6,700 to 7,000 men, of the infantry regiment 3,620 men and of the infantry battalion 1,022 men. The 21 field artillery battalions averaged between 520 and 560 men.
The Leningrad Front’s 23rd Army was assigned the task of making the breakthrough at Vuosalmi. For this task 23rd Army initially assigned the LXXXXVIII Corps and later replaced this with the CXV Corps. General Leytenant Georgi I. Animisov’s LXXXXVIII Corps comprised 92nd Division, 281st Division and 381st Division, while General Major Sergei B. Kozatchek’s CXV Corps comprised the 10th Division, 92nd Division and 142nd Division. Alo committed to the battle was the VI Corps with the 13th Division, 382th Division and 327th Division, and the 23rd Army’s support elements were the 17th Fortification Area, the 47th Guards Artillery Brigade, the 21st, 151st and 336th Artillery Regiments, the 165th, 641st, 883rd and 1072nd Anti-Tank Regiments, the 175th, 456th, 506th and 567th Mortar Regiments, the 70th Guards Mortar Regiment, the 1469th Anti-Aircraft Regiment, the 71st and 618th Separate Anti-Aircraft Battalions, the 46th Guards Tank Regiment, the 226th Tank Regiment, the 938th and 952nd Self-Propelled Gun Regiments, the 71st Separate Armoured Train Battalion and the 20th Engineer Brigade. The Soviet strength was thus eight infantry divisions, between 80 and 90 tanks and self-propelled guns, and about 600 pieces of artillery and heavy mortars. The average strength of the Soviet infantry divisions was between 6,600 and 6,700 men.
The Finnish positions were tactically poor as they were located on the Äyräpää river, with the wide Vuoksi river behind them. Though the position was very unfavourable, the Äyräpää ridge dominated the lower ground to its north-east, and it was this which had led to the decision to site the defensive line on the ridge.
The Soviet LXXXXVIII Corps began it main assault on 4 July and heavy fighting raged for control of the ridge until 9 July, when Finns finally withdrew to the northern bank of the river. The Soviet CXV Corps then continued the attack and crossed the Vuosalmi river on 9 July. During that day both the Soviet and Finnish forces fired their largest numbers of artillery rounds and mortar bombs: 30,000 by the Soviets and 18,800 by the Finns, 13,500 of the latter being artillery rounds.
The CXV Corps then reinforced its bridgehead across the Vuoksi river, and had all three of its divisions in the bridgehead by 11 July. The Finnish forces also received reinforcements in the form of the depleted Panssaridivisioona directly from Ihantala, and on 11 July both sides tried to attack simultaneously. The side’s attempts were halted when they ran into attacking enemy formations. Although the Soviets now had access to the land on the river’s northern side, which were well suited to armoured operations, the Finns were able to stop any further Soviet advance. The following Finnish counterattacks were no more successful, and thus both sides went over to the defensive in the middle of July.
In total, the Finnish field artillery had fired more than 122,000 rounds in the area of Äyräpää and Vuosalmi between 20 June and 17 July: this was basically the same number as it had fired in the 'Battle of Tali-Ihantala', which was fought over almost exactly the same period in a nearby area of the relatively narrow Karelian isthmus. The Finnish mortar units had fired 85,000 bombs. When comparing the eight-day period of the most intensive fighting, considerably a greater number of artillery rounds had been fired at Vuosalmi (74,000) than at Tali-Ihantala (56,000). During that same period, in the Vuosalmi sector the Finns' mortar units fired 52,000 bombs.
Govorov, the commander of the Leningrad Front, strongly criticised heavily the commanders of the 23rd Army, the LXXXXVIII Corps and the CXV Corps for gaining only the most modest of successes in the 'Battle of Vuosalmi', and then at the expense of very heavy casualties.