Japan during World War II reconstruct the "'critical mass' of both large numbers of carriers and well-trained air groups". Australian land forces defeated Japanese Marines in New Guinea at the Battle of Milne Bay in September 1942, which was the first land defeat suffered by the Japanese in the Pacific. Further victories by the Allies at Guadalcanal in September 1942, and New Guinea in 1943 put the Empire of Japan on the defensive for the remainder of the war, with Guadalcanal in particular sapping their already-limited oil supplies. During 1943 and 1944, Allied forces, backed by the industrial might and vast raw material resources of
Declarations of war during World War II 1907 (or Hague II). For the diplomatic maneuvering behind these events, which led to hostilities between nations during World War II, see the article entitled Diplomatic history of World War II. Below is a table showing the outbreak of wars between nations which occurred during World War II. Indicated are the dates (during the immediate build-up to, or during the course of, World War II), from which a "de facto" state of war existed between nations. The table shows both the "Initiator Nation(s)" and the nation at which the aggression was aimed, or "Targeted Nation(s)". Events listed include those in