What phrase did Japan use as the radio signal confirming the Pearl Harbor attack’s success?

Japan used the phrase “Tora! Tora! Tora!” as the radio signal confirming surprise had been achieved at Pearl Harbor.

The phrase was transmitted by Commander Mitsuo Fuchida, who led the first attack wave. In this context, it was understood as an abbreviation for tora, tora, tora—“tiger, tiger, tiger”—and indicated that the attacking force had achieved complete surprise.

The expression became widely known after the 1970 film Tora! Tora! Tora!, which dramatized the attack and the events leading to it. The film title is therefore based on a real wartime signal, not an invented slogan.

The phrase did not mean that Japan had won the entire war. It reported the tactical success of the opening attack, which began shortly before 8 a.m. Hawaii time.