Final answer:
Germany lost an important World War II ally when Japan surrendered on August 15, 1945, which marked the end of the Tripartite Pact and weakened Germany's strategic position significantly.
Step-by-step explanation:
Germany lost a crucial ally in World War II when Japan surrendered on August 15, 1945, after the atomic bombings of Hiroshima and Nagasaki by the United States. This event marked the effective end of the Tripartite Pact, a defensive military alliance formed in 1940 between Germany, Italy, and Japan.
The pact was originally designed to frighten the United States away from supporting their enemies and to extend Axis power across Europe and Asia. However, the surrender of Japan eliminated the Axis powers' presence in Asia and weakened Germany's overall strategic position in the war. By this point, Germany had already been suffering setbacks, with the Allies landing in Normandy on D-day and pushing back German defenses in Europe. Eventually, without its Eastern ally, and with the Allied forces closing in, Germany surrendered on May 8, 1945, marking the end of the war in Europe.