During the interwar period, aircraft and tank technologies matured and were combined with systematic application of the traditional German tactic of (manoeuvre warfare), deep penetrations and the bypassing of enemy strong points to encircle and destroy enemy forces in a (cauldron battle). During the Invasion of Poland, Western journalists adopted the term "blitzkrieg" to describe this form of armoured warfare. The term had appeared in 1935, in a German military periodical (German Defence), in connection to quick or lightning warfare. German manoeuvre operations were successful in the campaigns of 1939–1941 and by 1940 the term "blitzkrieg" was extensively used in Western media. Blitzkrieg operations capitalized on surprise penetrations (e.g., the penetration of the Ardennes forest region), general enemy unreadiness and their inability to match the pace of the German attack. During the Battle of France, the French made attempts to re-form defensive lines along rivers but were frustrated when German forces arrived first and pressed on.