"Tora Tora Tora" was the Japanese code used to indicate maximum success in their attack on Pearl Harbor, Hawaii, on December 7, 1941. The word "tora" means tiger, and it is an abbreviation of a longer Japanese phrase that can also be interpreted as "lightning attack". The Japanese attack on Hawaii was unexpected at 7:55 am, early on a Sunday morning. This caught the Americans stationed there completely off guard, and the attack was a success. The attack on Pearl Harbor led the United States to join the war against the Axis powers in World War II.