The
Finnish Army mobilized on 10 June 1941 in preparation for the
Continuation War, the Finnish component of the
German invasion of the Soviet Union. This followed Finno-German negotiation that had been ongoing from at least May 1941. The VII Corps was formed around the headquarters of the peacetime IV Corps and consisted of the
11th,
7th and
14th divisions. Commanded by
Major General Woldemar Hägglund, the corps initially took defensive positions in the area between
Ilomantsi and
Pyhäjärvi as the second northernmost Finnish corps. To its north was the
III Corps, which was subordinated to the German
Army High Command Norway. The VII Corps sector was soon shortened by subordinating the northernmost division of the corps, the 14th, directly to the Finnish General Headquarters. In return, the corps was reinforced with a formation called Group O () which consisted of three brigades. To its south was the
II Corps. As the Finnish preparations continued in the days following the start of the German invasion on 22 June, the Finnish
commander-in-chief Marshal Carl Gustav Emil Mannerheim had concerns regarding the situation of the Finnish forces preparing to attack into
Ladoga Karelia. With multiple corps planned to attack in three different directions, the operation was too complicated to be left uncoordinated by a higher echelon. At the same time, any attempt by the Finnish General Headquarters to directly coordinate the actions in the region would have disturbed its ability to properly supervise actions on other fronts. As such, on 29 June Mannerheim ordered the creation of the
Army of Karelia to coordinate the actions in the region. The creation of the new army headquarters resulted in a significant reordering of the corps in the region. During this reorganization, VII Corps was moved to the southern flank of the Army of Karelia into a region spanning from the line
Onkamo-
Vyartsilya in the north to
Pyhäjärvi in the south. Following the reorganization, the corps consisted of the
19th and 7th Divisions. Of these, the 7th was on the north-eastern (left) flank while the 19th was on the south-western (right) flank. The initial plan was for both divisions to strike southeast, with the 7th Division taking
Matkaselkä and the 19th Division taking
Kaalamo. The corps was ordered to push the Soviet forces in its sector toward either Lake Ladoga or
Jänisjoki. Concurrently, other forces of the Army of Karelia would attack to the north of
Lake Yanisyarvi before turning south. Together, these two movements would trap Soviet formations on the isthmus between Lake Ladoga and Lake Yanisyarvi. The attack would then continue to the
Svir and
Lake Onega. However, a lack of artillery, as well as intelligence regarding Soviet preparations in the area, forced the plan to modified. Instead of advancing directly to the Lake Ladoga at
Sortavala, VII Corps would advance along the shore of Lake Yanisyarvi. ==Invasion of Ladoga Karelia==