🪜 Ladder Game (Amidakuji / Ghost Leg)
Enter names and outcomes, then tap a name to follow its path down the ladder. Great for deciding who buys coffee, who goes first or who does the dishes.
How to play the ladder game online
- Set the number of players (2–12) with − / + and type everyone's name. Blank names show as "Player 1", "Player 2" and so on.
- Fill in the results at the bottom of the ladder — or tap a preset: 1 winner, 1 penalty, Who buys coffee or Turn order.
- Tap a name at the top of the ladder to watch that player's path drawn in color; the result they land on is revealed.
- Reveal all sends everyone else down at once and lists the results. copy grabs the "name → result" list for your group chat.
- To keep it fair, only hit Reshuffle before anyone starts — it redraws every rung from scratch.
Hide results (on by default) covers the bottom with "?" and opens each slot only when someone lands on it, just like a paper ladder with the bottom folded over. Turn it off to show all outcomes from the start.
What is the ladder game (Amidakuji / Ghost Leg)?
It is a lottery drawn as a ladder: vertical lines, one per player, with random horizontal rungs between neighbors. It is called Amidakuji in Japan, Ghost Leg (鬼腳圖) in China and Taiwan, and sadari-tagi (사다리타기) in Korea, where it is the go-to way to settle a bet. The rule is simple: start at the top and go down; whenever you meet a rung, you must cross it to the neighboring line, then keep going down until you reach the bottom.
Rungs never touch the same line at the same height from both sides, so paths never split or merge and no two players can end up on the same result. Mathematically, a ladder is a permutation — it hands out the results one-to-one.
Is a ladder game fair? The rung problem
A hand-drawn ladder is less fair than it looks. Each rung only swaps two neighbors, so with few rungs most players finish directly below or near where they started. On a 6-player ladder with only 5–6 rungs, the far-left player would need to cross five rungs in a row to reach the far-right result — very unlikely. Someone who picks the starting spot above the prize really does have an edge.
Mixing a ladder evenly with random rungs takes roughly n² rungs for n players (the same problem as shuffling cards by swapping neighbors) — dozens to a hundred for 10 people, far more than anyone draws by hand.
Why this ladder is fair
- First,
crypto.getRandomValuesand a Fisher-Yates shuffle choose one of the n! possible outcomes with exactly equal probability. - A block of rungs that produces exactly that outcome (odd-even transposition sort, run backwards, at most n rows) goes in the middle, with extra random rungs above and below so it looks natural.
- Because the middle block is perfectly uniform and independent of the rest, the final outcome is still uniform no matter what the other rungs do. Every starting spot has exactly a 1/n chance of any given result.
| Players | Possible outcomes (n!) | Chance a given player wins |
|---|---|---|
| 2 | 2 | 50% |
| 3 | 6 | 33.3% |
| 4 | 24 | 25% |
| 5 | 120 | 20% |
| 6 | 720 | 16.7% |
| 8 | 40,320 | 12.5% |
| 10 | 3,628,800 | 10% |
| 12 | 479,001,600 | 8.3% |
Ideas for using it
- Coffee or lunch bets — one "Buys coffee" slot, everyone else "Free coffee". Want two people to pay? Edit a second slot.
- Presentation or turn order — the Turn order preset fills #1 to #n. For long lists, the random name picker's order mode is faster.
- Chore chart — put "Dishes", "Trash", "Groceries" in the result slots.
- Gift exchange or seating — share your screen or pass the phone around so everyone taps their own name.
Names and results are saved only in this browser (localStorage) for next time and never sent to a server. A new ladder is generated every time you reshuffle.