Did Mr. Takagi actually know the code key to the vault?

Question

In Die Hard Hans Gruber and his associates take Nakatomi Plaza hostage in hopes of stealing $640 million in bonds. Hans needs a code key password from Mr. Takagi to easily access the vault.

Mr. Takagi repeatedly tells Hans that he just doesn't know it:

Takagi: I don't have that code. You broke in here to access our computer? Any information you could get... ..when they wake up in Tokyo, they'll change it. You won't be able to blackmail our executives...

Gruber: Sit... down! Mr Takagi, I'm really not interested in your computer. But I need the code key... ..because I am interested in the $640 million... ..in negotiable bearer bonds that you have locked in your vault... ..and the computer controls the vault.

Takagi: You want money? What kind of terrorists are you?

Gruber: Who said we were terrorists? The bonds represent, at most... ..10 days' operating capital for your parent organisation. It's really no more than a temporary inconvenience. Now... ..the code, please.

Takagi: It's useless to you. There are seven safeguards on our vault and the code key's only one of them. You'll never get it open.

Gruber: Then there's no reason not to tell it to us.

Gruber: It's a very nice suit, Mr Takagi. It would be a shame to ruin it. I'm going to count to three. There will not be a four. Give me the code. One,... ..two,... - ..three,...

Takagi: - I don't know it. Get on a jet to Tokyo and ask the chairman. You're just gonna have to kill me.

Gruber: OK.

Is there any evidence that Mr.Takagi knew the code key? Mr. Takagi is almost arrogant when he tells Hans that he is going to have to kill him. Was Mr. Takagi already aware that Gruber would kill him whether he told him or not?

Answer 1

Is there any evidence that Mr.Takagi knew the code key?

No, there is no evidence that Mr. Takagi knew the code key. During this conversation, he tells that I don't know the code key all the time.

Takagi: I don't have that code. You broke in here to access our computer? Any information you could get... ..when they wake up in Tokyo, they'll change it. You won't be able to blackmail our executives...

Was Mr. Takagi already aware that Gruber would kill him whether he told him or not?

Mr. Takagi was already aware that Gruber would kill him whether he told him or not. We can see him sweating when he was talking to Gruber.

They can easily break into the vault without the key as turned out later in the movie. Hans Gruber was trying to get the key from Mr. Takagi because a code key will simply make their work easier and save them hours of trying. Even if he knew the code key, they'd have killed him because he was no longer of their use. And since he told that he does not know that code, he is no use of them. Mr. Takagi already knew, possibly, about it.

Answer 2

I'm going to contradict the accepted answer and say that Mr. Takagi knew the key because the key is shown to the audience on Theo's computer monitor as "Red Castle", and visual cues are given showing "Red Castle's" derivation from "Akagi". This seems too coincidental for me.

Why did Mr. Takagi choose to lie to Hans? Mr. Takagi likely suspected that the lives of himself and his employees were forfeit the minute the terrorists got their hands on the vault, and he viewed his life as a necessary sacrifice to buy time.

This was the smartest move he could make, as the terrorists were planning on killing everyone by blowing the roof. Ultimately his sacrifice was in vain as the terrorists' plan was bottlenecked by FBI intervention.