Do you know "Rock, Scissors, Paper"?

Today's question is "do you know Rock-Scissors-Paper?"
Probably many people say "yes".

And I know in France they do Rock-Scissors-Leaf( instead of Paper)-Well. Because Lea told me.
(Lea, can you see it? I hope you could reach my blog.)

But, it is the first question, what do you call kind of this game?
In Japan we call it Janken.

And I found this Janken site.

To tell the truth, before I found this site, I had thought that in the U.S.A they didn't have Janken." Because some of my "adult" guests who came to stay with us said "what were you doing?" when my daughters did that.

And from them I was heard that they usually use a coin to decide who goes first saying "heads or tails".
Well, it is the next question.
Please tell me more specifically the rule of the way of even or odd.
My understanding is like that.
There are five members.
Everyone indicates a number using their shingle hand saying even (or odd).
And they count the total number.
If it is an odd number, the people who indicate numbers of odd (1, 3, 5) are winner.

Well, if my understanding is right, I'll ask another question.
How do you indicate "zero".
If you use only one hand, odd numbers are 1,3,5. So even numbers has to exist as much as the numbers of odd numbers. probably 2, 4, and 0