Yenshin transferred in May 1935 to become head of the 1st Kalevala NKVD Border Detachment at Ukhta before becoming head of the 37th NKVD Border Detachment at Batumi in December 1937. He studied at the Order of Lenin Higher NKVD School in Moscow from October 1939, but was seconded to the Northwestern Front in December, with which he fought in the Winter War as commander of the 2nd Border Regiment of the 9th Army in the Kandalaksha sector. For his "courage in battle", Yenshin received the Order of the Red Banner on 26 April 1940. After the end of the war he returned to the Higher NKVD School, and upon graduation in January 1941 became a military instructor at the academy.