The stone bridge over the River Iljanjoki marked the pre-war border between Finland and the Soviet Union. The Soviet summer offensive of 1944 met great success on the Karelian Isthmus, and Red Army officers expected similar results farther north. But when their enemies set foot in pre-war Finland, a new resolve took hold in the Finnish troops. The two companies detailed to hold the bridge took up hidden positions on either side of the river, determined to make the Soviets pay for entering Finland.

The Finns disrupted the Soviet advance when their small anti-tank battery, emplaced on the east bank of the river where the Soviets never expected to meet resistance, knocked out several tanks and a hidden ambush set several more alight. When the first Soviet soldier splashed across the river, the Finns became possessed by the fighting rage known as sisu and poured out of their positions to engage the Red Army hand-to-hand. Stunned by the assault, the Soviet 55th Rifle Regiment broke and fled, hotly pursued by a force a fraction of its size. Soviet officers finally got hold of their troops on Vellivaari hill.