From Wikipedia:
“… Japanese codeword used to indicate that complete surprise had been achieved. Tora literally means ‘tiger’ but in this case was an acronym for totsugeki raigeki ‘lightning attack’.”
Am in right thread and am not your friend.
Francis?
As in His Holiness?
As in Assisi?
I must be making an even better impression than I intended! (except on Brother Colibri).
Damn straight! 
Really? Kids these days…
https://www.youtube.com/watch?v=0OnpkDWbeJs
HaHaHaHaHa.
But that Francis guy reminds me of a certain moderator more than it reminds me of myself.
Which was APT, since a tiger does a lightning attack.
Too bad they weren’t attacking a target for which their shots caused useful attrition, or caused the enemy to divert or forgo or lose resources… The tiger attacked a target that wasnt worth much, no flesh, and broke a few teeth on the bones.
Was just scrolling down to post the exact same thing.
Also, note… *Francis * does not understand the origin.
BTW, that Francis statement is 35 years old and I swear I hear it at least once a month.
Why is the code word unprintable now?
Moderator Warning
Insulting a moderator immediately after receiving a warning for insults is not a wise course of action. This is an additional warning.
Colibri
General Questions Moderator
Moderator Note
Mocking isn’t appropriate for GQ either. If you want to mock someone for any reason, take it to the Pit. No warning issued.
Colibri
General Questions Moderator
The codeword to indicate the breech of the Möhne Dam was the name of Gibson’s dog, which was hit by a car and died the day before the mission. The dog’s name was ‘[N-word]’ (most likely referring to Indians, rather than Africans), and that word is taboo.
In any case, ‘Tora = Tiger’ makes sense from a Western perspective because codewords – actual words – are common in Western military forces. Gibson used a codeword to indicate the success of his mission. Pilots use ‘bandit’, ‘bingo’, and ‘Winchester’ as codewords to indicate an enemy aircraft, they have minimum fuel to return to base, and they’re out of ammunition.
On the other hand, I am now leaning toward the consonant-vowel pairs because the Japanese Navy was known to use them, and they seem a natural progression from signal flags.
The code word for success was “Nigger”. That was the name of the squadron’s beloved mascot dog who had died just before the raid. Different times, different usages…
Glad to hear it. I was afraid we’d permanently lost some letters of the alphabet during the war, but people born since never knew because the letters could no longer be printed. 
I have not heard of the consonant-vowel pairs theory, either. AFAIK, “Tora” is Japanese for “tiger” and the coded message/phrase “Tora, tora, tora” issued on the morning of Dec 7 meant that complete surprise has been achieved.
The frequent use of the name in the film The Dambusters has resulted in it being censored when shown on TV. In more recent showings, the film has been shown with a warning for language at the beginning.
I don’t think any of that is in dispute. Where there is some question–and maybe something we’ll never know–is whether. . .
a) the code word was simply the word for ‘tiger’, implying that they had attacked like a tiger
b) the code word was two unrelated syllables that happened to translate to ‘tiger’
c) the code word was a sort of Japanese acronym that happened to translate to ‘tiger’.
I thought I’d just contact the Japan Maritime Self-Defense Force and ask them, but I couldn’t find a Public Affairs contact email.
d) the code word was simply the word for “tiger”, implied nothing about the nature of the attack, and indicated surprise had been achieved.
nm