3. Second Sino-Japanese War (1937-1945)
The Second Sino-Japanese War commenced on July 7, 1937, when Japanese forces initiated hostilities against China without a formal declaration of war (britannica.com). This conflict, one of the deadliest in history, resulted in millions of casualties and significant destruction. The lack of an official declaration complicated international diplomatic responses and heightened global tensions, as the war’s escalation intertwined with broader World War II dynamics.
