Unofficially WW II in the Western front ended with the surrender of the last major forces holding out in Berlin. In the Eastern front it ended when Japan signed the armistice announcing their unofficial surrender. Major hostilities ceased, but interestingly WW II for the United States technically went on for a full year more. This was more a legal decision than military one: a war government has a much different shape, and President Harry Truman needed time to demobilize and bring everything back to normality.
On this day, December 31, in 1946, President Truman called a News Conference on the Termination of Hostilities of World War II – still not a formal end to the war, he emphasized, but the end of the period of hostilities (which informally ended before the end of 1945.)
Some die-hard German partisans continued to resist the Allied occupation for years after the war, their “Operation Werewolf” conducted from the hills and forests where they hid out. A hardy handful of individual Japanese soldiers held out even longer – way longer. Because many were holed up in the dense jungles of the islands, isolated from the mainland or headquarters during the American island hopping campaign, they did not always get notifications of surrender. One, Lieutenant Hiroo Onoda, refused to come out for nearly three decades after Japan surrendered, dismissing those news as enemy propaganda. It took a trip to the Philippines by his commanding officer for Onoda to come out – his rifle still in operating condition.