The "1st, 2nd and 5th Nebelwerfer Battalions", each equipped with 24 "10 cm Nbw 35" mortars in three batteries, were ready when the Germans invaded Poland in September 1939. The "1st and 2nd Battalions" participated in that campaign, while the "5th" remained in Western Germany. One battery of "Artillery Regiment 222" was converted to "10 cm NbW 35s" and participated in the Norwegian Campaign. By May 1940, five more battalions had been formed, all equipped with "10 cm NbW 35" mortars, filling out the sequence from 1 to 8, but only the first five were combat ready when the Battle of France began on 10 May 1940.