On 30 November 1939, Zelentsov leading the Soviet 163rd Rifle Division (the 81st and Sharov's 662nd Infantry Regiments with tanks and cavalry) left
Ukhta and crossed the border near Juntusranta, while the 759th Infantry Regiment and Division reconnaissance battalion crossed at Raate, as the Soviets advanced towards
Suomussalmi. The Soviet objective was to advance to the city of
Oulu, effectively cutting Finland in half. At the road connecting Peranka with
Hyrynsalmi, the 662nd turned north intending to capture Peranka, while the 81st regiment turned south to join the 759th in attacking Suomussalmi. On 4 December, the Finnish Independent
battalion (ErP 15) and the 4th Field Replacement Battalion fought the Soviets from Raate to Suomussalmi, but Suomussalmi was captured on 7 December. On 6 December, I. Pallari's ErP 16 stopped the Soviet advance on Peranka at the
Piispajärvi straits.
Paavo Susitaival took over command of Task Force Susi north and east of the Palovaara junction, while Salske took command of ErP 16 after Pallari was wounded. By 9 December the
Hjalmar Siilasvuo's Regiment JR 27 had arrived, stopping the Soviet advance towards Hyrynsalmi at a ferry just south of Suomussalmi. By the 11th, JR 27 ha severed the Soviet Raate road communication link to the east of Suomussalmi. A Finnish battalion then cut off Soviet communications at Hulkonniemi, northwest of Suomussalmi. Over the next two weeks, Siilasvuo was able to contain the Soviets, while Finnish artillery arrived. On 25 December, Siilasvuo's forces were reorganized as the 9th Division, with the addition of Regiment JR 64, guerilla battalion Sissi P1, and bicycle battalion PPP 6. On 27 December, Task Force Susi, reinforced by Regiment JR 65, captured Palovaara, preventing the Soviet 662nd Regiment from supporting the rest of the 163rd Division. On 24 December, surrounded on all sides in the Hulkonniemi-Suomussalmi area, Zelentsov tried to break out to the south, but was stopped by JR 27's Second Battalion. On 25 December, the Soviets tried to break out to the west, but were once again stopped. On 27 December, Siilasvuo made his move, with Kaarle Kari attacking from the northwest along columns led by Frans Fagernäs and Martti Harola, while Battalion PPP 6 struck from the north, and Paavola prevented any northern movement along Lake
Kiantajärvi. On 28 December, around 9 A.M., according to Chew, "Russian resistance suddenly collapsed in front of Fagernäs, the men bolted from their positions, some towards Suomussalmi village, others onto the ice of Lake Kiantajärvi - a few throwing away their weapons in their haste. This retreat sealed the fate of the 163rd Division, although the battle continued against its remnants for two more days. The 163rd Division no longer existed - there were only a few hundred cold, hungry, frightened men who abandoned their weapons and fled in panic towards the Soviet border beyond Juntusranta, some 20 miles to the northeast. The rout developed into a slaughter..." ==Outcome==