The Finger Game

   Japanese kids have a bunch of variants on rock-scissors-paper that they play, but they also have the finger game. The finger game is usually fast-paced and generally only ends when someone makes a dumb mistake because they were trying to hurry. You see, it involves very basic math: addition and subtraction.

   The setup is pretty simple; two people play and decide who goes first. Then both players stick out their index fingers. The game itself is also pretty simple -- you reach out and touch the opponent's hand with your hand and they add the number of fingers you have stuck out.

   So if you have one finger stuck out and tap a hand that has two, that person sticks out one more finger for a total of three. If you have three fingers stuck out and tap a hand that has three, that person goes down to one finger, because six minus five (the maximum number of fingers normal people have) is one. If you have two fingers stuck out and tap a hand that has three, that makes a total of five, and that hand is "out." You win the game by getting both of a player's hands "out."

   Additionally, since you have two hands, you can swap fingers between them. So if you have four fingers out on one hand and your other hand is out, then you can tap them and give them both two fingers, or give one three and the other one. The thing to consider is how many fingers your opponent has out on each hand -- if they have three fingers out on one, then going two and two isn't the best idea since they'll immediately knock one of your hands out, even though you can knock that three hand out.

   It sounds confusing when described like this, but it's really pretty simple.

   Does this game exist in America?