He was a private with the 423rd Infantry Regiment , 106th Infantry Division . Vonnegut was captured during the Battle of the Bulge on December 19 , 1944 . As a private with the 423rd Infantry Regiment , 106th Infantry Division , Vonnegut was captured during the Battle of the Bulge on December 19 , 1944 , after the 106th was cut off from the rest of Courtney Hodges ' First Army .