Amidakuji Generator
Create an animated ladder lottery (Ghost Leg).
Share the URL so everyone can draw lots on their own phones.
About
Easily create an "Amidakuji" (Ladder Lottery) in your browser. Perfect for deciding who pays the bill, assigning tasks, or exchanging gifts.
Just input the participant names and possible results. The ladder is generated automatically. The animated tracing adds suspense and excitement!
You can share the generated ladder via a URL link, allowing friends and colleagues to trace their own paths on their smartphones.
How to Use
Input Data
List participants and results (one per line). Both lists must have the same number of items.
Draw Lots
Click 'Create' to see the ladder. Tap a name at the top to watch the animated path down to the hidden result.
Share with URL
Click 'Share' to copy an encoded link. Send it to friends so they can draw on their own devices.
Glossary
- Amidakuji (Ghost Leg)
- A traditional Japanese lottery method consisting of vertical lines and horizontal connecting "bridges." Participants choose a top starting point and follow the line downwards; every time they hit a horizontal bridge, they must turn horizontally to the adjacent vertical line, eventually reaching a hidden result at the bottom. It guarantees a fair, 1-to-1 mapping of inputs to outputs.
- Horizontal Lines (Bridges)
- The rungs connecting adjacent vertical lines in an Amidakuji. These bridges alter the path, creating unpredictable results.
- Random Generation
- A feature that uses a program to randomly determine the position and number of horizontal lines. Unlike hand-drawn ladders which can show bias, this ensures a perfectly balanced and fair distribution.
- Animated Tracing
- A visual feature that tracks the path from the starting point to the result. It displays the movement along the lines in real-time, building anticipation before revealing the outcome.
- Canvas Rendering
- A technology using the HTML5 Canvas element to draw the Amidakuji lines and animations directly in the browser, providing instant results without requiring server communication.
- Participant Setup
- The function to set the number of people participating in the draw and their names. You can also customize the number of winning (prizes) and losing outcomes freely.
- Result Fairness
- Mathematically, an Amidakuji is equivalent to a "permutation." Provided the placement of horizontal lines is sufficiently random, it is algebraically guaranteed that every participant has an equal probability of reaching any given outcome.
FAQ
- Q.Are the Amidakuji results sent to a server?
- No. All generation, drawing, and result calculation are completed entirely within your browser. Participant names and outcomes are never sent to our servers.
- Q.Is there a limit to the number of participants?
- We recommend using 2 to 20 participants for optimal viewing. It is technically possible to have more, but the lines may become too dense and difficult to read.
- Q.Is the result truly random?
- Yes. The positions of the horizontal lines are determined by JavaScript's random number generation, resulting in a perfectly fair draw with no bias, unlike hand-drawn ones.
- Q.Can I redo the draw?
- Yes. By clicking the "Edit" button, you can generate a new arrangement of horizontal lines and instantly hold another draw.
- Q.Can I use it from a smartphone?
- Yes. It supports touch operations and can be used on your smartphone or tablet's browser. It's perfect for on-the-spot situations like drinking parties or classroom seat changes.
- Q.Can I save the Amidakuji results as an image?
- Yes. After the results are displayed, you can use the image save feature to save the entire Amidakuji diagram as a PNG image.
- Q.Can I change the number of "winners" and "losers"?
- Yes. You can freely set the prizes or roles. Besides "Winner" or "Loser", you can enter custom text to accommodate a wide variety of draws.
Use Cases
Paying the Bill
Turn deciding who pays the restaurant bill into a fun mini-game.
Task Assignment
Assign chores, presentation order, or roles randomly and fairly.
Secret Santa / Gift Exchange
Determine who gives a gift to whom using the ladder.
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Please let us know your thoughts to help us improve the tool.
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