In December 1944 the Oberkommando der Wehrmacht and Hitler resolved to improve Germany's military situation by beginning an offensive on the Western Front. Codenamed "Wacht am Rheine", the Ardennes Offensive. JG 1 was ordered to form part of the Luftwaffe's order of battle. ULTRA intercepts deciphered messages to and concerning JG 1 and the German build up which suggested the Wehrmacht was preparing for offensive action. ULTRA accurately identified a 24-25 "gruppen" force, and suspected 600 to 700 fighters had been brought in from strategic defence for whatever operation was to take place. JG 1 was mentioned in the report, alongside JG 3, JG 4, JG 11, JG 26, JG 27, JG 77, JG 300 and JG 301. All three "gruppen" moved to the Netherlands. II. "Gruppe" were based at Drope, on the Dutch border in the winter, 1944/45.