The Japanese successfully sever the Trans-Siberian Railway, cutting off shipments to Vladivostok. Cold weather and mosquitoes take their toll on the Japanese soldiers, and skirmishes with Soviet partisans are common. Despite the distance from the industrial areas of Russia, Soviet forces maintain modest air and artillery superiority, but their accuracy is often doubtful, causing many casualties on both sides. Japanese attacks on Vladivostok proceed much like their attacks on Port Arthur in 1904, suffering tremendous casualties and gaining very little ground.