How to Use Ladder Lottery: Complete Beginner's Guide, 2025 Edition

"What is ladder lottery?" "How do you draw it on paper?" "Want to know online methods"

Ladder lottery (Amidakuji) is a fair lottery method used in Japan since ancient times. It's utilized in various settings including schools, companies, and homes for role assignment and order decisions.

This article explains ladder lottery basics to online version usage methods clearly for beginners.

What is Ladder Lottery? [Basics]

Ladder Lottery Definition

Ladder lottery (Amidakuji) is a lottery method using multiple vertical and horizontal lines.

Basic structure:

Participant names
  ↓
Vertical lines
  | Connected by horizontal lines
  | /
  | /
  |/
Results (win/lose, roles, etc.)

Characteristics:

• High fairness
• Anyone can do easily
• Transparent
• Difficult to manipulate

Ladder Lottery History

Origin:

• Existed since Muromachi period (15th century)
• Used by monks
• Named "Amida-kuji" because resembles Amida Buddha's halo

Modern use:

• Schools: Cleaning duty, presentation order
• Companies: Meeting role assignment, lotteries
• Homes: Chore distribution, order decisions
• TV programs: Game order decisions

Why Ladder Lottery is Used

Reason 1: Fairness

• No one can manipulate results
• Everyone has equal chance
• Mathematically proven fairness

Reason 2: Transparency

• Process visualized
• Everyone easily satisfied
• Unfairness easily noticed

Reason 3: Simplicity

• Can do with paper and pen
• No special knowledge needed
• Children can understand

Creating Ladder Lottery on Paper [Step by Step]

What You Need

• Paper
• Pen (or pencil)
• Participant name list
• Results list (roles, prizes, etc.)

Creation Steps (5-person example)

Step 1: Draw Vertical Lines

Draw vertical lines for number of participants

Example: 5 people
|  |  |  |  |
|  |  |  |  |
|  |  |  |  |
|  |  |  |  |

Spacing: ~2-3cm

Step 2: Write Participant Names at Top

Tanaka Sato Suzuki Yamada Takahashi
 |    |    |     |      |
 |    |    |     |      |
 |    |    |     |      |
 |    |    |     |      |

Step 3: Add Horizontal Lines

Important rules:

• Horizontal lines connect only adjacent vertical lines
• Horizontal lines don't overlap (don't cross)
• Number of horizontal lines is free (more = fairer)

Tanaka Sato Suzuki Yamada Takahashi
 |    |    |     |      |
 |----+    |     |      |  ← Line 1
 |    |    |-----+      |  ← Line 2
 |    |----+     |      |  ← Line 3
 |    |    |     |------+  ← Line 4
 |    |    |     |      |

How to add lines (increase fairness):

1. Participants randomly add horizontal lines
2. Roll dice to decide position
3. Draw from enveloped papers to decide

Step 4: Write Results at Bottom

Tanaka Sato Suzuki Yamada Takahashi
 |    |    |     |      |
 |----+    |     |      |
 |    |    |-----+      |
 |    |----+     |      |
 |    |    |     |------+
 |    |    |     |      |
A    B    C     D      E

A=Minutes, B=Facilitator, C=Timekeeper, D=Scribe, E=None

Step 5: Trace Lines

Trace top to bottom for each participant.

Tracing rules:

• Move from top to bottom
• If horizontal line exists, must move horizontally
• If no horizontal line, continue down

Example: Tanaka's case

Tanaka
 ↓
 |----+  ← Horizontal line, move right
      ↓
      |
      B

Result: Tanaka → B (Facilitator)

Common Mistakes

Mistake 1: Crossing Horizontal Lines

 |   |
 |---+---+  ← Wrong (3+ lines connect)
 |   |

Correct:

 |   |   |
 |---+   |  ← OK (only 2 connect)
 |   |---+  ← OK
 |   |   |

Mistake 2: Separated Horizontal Line

 |   |   |
 |--    -|  ← Wrong (not connected)
 |   |   |

Correct:

 |   |   |
 |-------+  ← OK (definitely connected)
 |   |   |

Mistake 3: Vertical Line Breaks Mid-Way

 |   |
 |   |
     |  ← Wrong (disappeared mid-way)
 |   |

Correct:

 |   |
 |   |
 |   |  ← OK (one line top to bottom)
 |   |

Using Online Ladder Lottery

How to Use Amida-san [Recommended]

URL: https://amida-san.com

Features:

• No registration, completely free
• Supports up to 299 people
• All participants add horizontal lines
• Permanent URL storage

How to use (5 steps):

Step 1: Create Event (1 min)

1. Access Amida-san
2. Click "Create Event"
3. Input event name (e.g., "Today's Role Assignment")
4. Input results (goals)
   Minutes
   Facilitator
   Timekeeper
   Scribe
   None

Step 2: Share URL (10 sec)

1. Click "Create Event"
2. URL displayed
   Example: https://amida-san.com/events/abc123
3. Copy URL
4. Share via chat/email

Step 3: Add Horizontal Lines (3-5 min)

1. Participants access URL individually
2. Click "Add Line" from smartphone/PC
3. Everyone adds 2 lines each
4. Line positions random

Step 4: Execute Lottery (10 sec)

1. All horizontal lines added complete
2. Click "Start Lottery"
3. Lines automatically traced
4. Results displayed

Step 5: Confirm Results (1 min)

【Results】
Tanaka → Facilitator
Sato → Minutes
Suzuki → None
Yamada → Scribe
Takahashi → Timekeeper

Permanent URL storage/verification

Online Version Merits

1. Large Capacity Support

• Paper: ~10 people limit
• Online: Up to 299 people

2. Remote Support

• Usable in Zoom/Teams meetings
• Each person can participate from smartphone
• Zoom meeting lottery

3. Recordability

• Permanent URL storage
• Verifiable afterward
• No screenshots needed

4. Transparency

• All participate in line addition process
• No one can manipulate results
• Unfairness impossible

5. Entertainment Value

• 3D production option (1,490 yen)
• Animation
• Exciting

Scene-Specific Ladder Lottery Applications

Scene 1: Schools/Education

Usage examples:

• Cleaning duty
• Presentation order
• Group leaders
• Seat assignments

Paper vs Online:

【Elementary School】 → Paper recommended
Reason: No smartphone allowed, educational value

【University/High School】 → Online recommended
Reason: High smartphone ownership, remote support

Practical examples:

• Fair school decisions
• Seminar assignment

Scene 2: Companies/Workplaces

Usage examples:

• Meeting role assignment
• Sales customer assignment
• Training group division
• Company event lottery

Paper vs Online:

【Small Meeting (5-10 people)】 → Paper OK
Reason: Quick, easy

【Remote Meeting】 → Online essential
Reason: Cannot gather physically

【Large Event (50+ people)】 → Online essential
Reason: Difficult to manage with paper

Practical examples:

• Fair role assignment
• Company event lottery

Scene 3: Home/Friends

Usage examples:

• Chore duty
• Travel room assignments
• Game order
• Meal treat decisions

Paper vs Online:

【Family (3-5 people)】 → Paper recommended
Reason: Easy, communication

【Friends Group (10+ people)】 → Online
Reason: Easy to share on LINE/chat

Scene 4: Events/Parties

Usage examples:

• Wedding reception lottery
• Bingo alternative
• Gift exchange
• Team division

Paper vs Online:

【Small-scale (10 or fewer)】 → Paper
Reason: Exciting, handmade feel

【Large-scale (50+)】 → Online
Reason: Easy management, remote participation possible

Practical examples:

• Online lottery best practices

Tips for Better Use

Tip 1: Increase Horizontal Lines

Reason:

• Increases fairness
• Makes prediction difficult
• Improves acceptance

Guidelines:

3-5 participants: 5-10 horizontal lines
10 participants: 15-20 horizontal lines
20+ participants: 30+ horizontal lines

Tip 2: Participants Add Horizontal Lines

Methods:

• Each participant adds 1-3 lines
• Decide position with dice
• Draw from envelopes

Effect:

• Everyone easily satisfied
• Transparency increases
• Unfairness impossible

Tip 3: Record Results

For paper:

• Photograph with smartphone
• Save copy

For online:

• Save URL
• Take screenshot

Reason:

• Verifiable afterward
• Trouble prevention
• Remains as record

Tip 4: Explain Rules in Advance

What to explain:

1. Ladder lottery mechanism
2. Horizontal line addition method
3. Result decision method
4. Complaint acceptance presence

Effect:

• Everyone satisfied
• Trouble prevention
• Smooth progress

FAQs

Q1: Is ladder lottery really fair?

A: Yes, mathematically proven fairness. With proper line addition method, everyone has equal probability of reaching each result.

Q2: Paper or online, which is recommended?

A:

• Small group (5 or fewer), in-person: Paper
• Large group (10+), remote: Online (Amida-san)

Q3: How many horizontal lines should I add?

A: 2-3 times participant count is guideline. For 10 people, 20-30 lines. More increases fairness.

Q4: Can ladder lottery be unfair?

A: With paper, theoretically possible by intentionally placing lines. However, with online version (Amida-san), everyone adds lines, making unfairness impossible.

Q5: Usable by children?

A: Yes, understandable from mid-elementary school. High educational value if carefully explained and created together.

Q6: Limits on vertical/horizontal lines?

A:

• Paper: ~10 vertical, ~30 horizontal limit (depends on paper size)
• Online (Amida-san): 299 vertical, unlimited horizontal

Q7: Usable from smartphone?

A: Yes, Amida-san optimized for smartphone browsers, easy line addition with tap.

Summary: Fair Decisions with Ladder Lottery

Ladder lottery is loved in Japan as a fair, transparent, simple lottery method.

Usage points:

1. Paper: Best for small groups, in-person
2. Online: Best for large groups, remote
3. More horizontal lines (improve fairness)
4. All participants add lines (improve transparency)
5. Record results (verifiable)

Recommended tools:

• Paper: In-person, 5 or fewer
• Amida-san: 10+ people, remote, record priority

Try ladder lottery at your next role assignment or lottery.

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Related articles:

• Ladder Lottery Mechanism and Fairness
• Mathematically Proven Fairness
• Fair Role Assignment Methods
• Online Lottery Best Practices