Janken

Rock, paper, scissors — for real money

Janken is rock-paper-scissors with money on it. You stake SOL, ETH or FUEL, get matched against an opponent, and play a best-of-three: first to win two rounds takes the pot. Rounds are fast and there is nothing to learn — the whole game is whether you can read someone you cannot see.

PLAY JANKEN

How to play

  1. Pick your token and stake, then join the queue. You are matched with another player betting the same amount in the same token.
  2. Throw your hand within 6 seconds. Miss the window and a hand is thrown for you, marked AUTO on the reveal.
  3. Both hands are locked before either is shown. Win the round and you take a point; a draw is aiko and the round is simply replayed with the score untouched.
  4. First to two rounds wins the match and takes 95% of the pot.
  5. If the queue is empty for about 8 seconds you are matched against a house bot instead, labelled CPU on screen. See below — those matches work differently.

Is it fair?

Against another player, neither of you can see the other's hand first: both hands are committed to the server before either is revealed, so there is no last-moment counter-pick and no advantage to a slower connection. Draws replay rather than resolving, so no round is ever decided by anything but two thrown hands. Against the house bot the arrangement is different and worth stating plainly. When nobody is in the queue you are matched with a CPU opponent and the house banks the match, so you are playing the house rather than a peer. That bot's hand comes from the same central RNG service the other house-banked games use, drawn at the start of each round before you throw. It is uniformly random every single round: it does not read your history, does not adapt to your pattern, and cannot counter what you are about to play. A rock-paper-scissors bot that learned your habits would beat you over time, so this one is deliberately built not to.

Stakes and payouts

Stake limits are 0.001 to 0.1 SOL, 0.001 to 0.1 ETH, or 200 to 20,000 FUEL, and both players in a match put up the same amount. The house takes a flat 5% of the pot and the winner receives the remaining 95% — the same rake Arena charges, and the entire house edge in a player-versus-player match.

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