Otto Mahjong · Reference Cards

The answer
in under five
seconds.

One card per player. Designed to sit in your hand during a live game and resolve the most common mid-game questions without stopping play — or the conversation.

Quick Ref
NMJL Decoder
Two Sides. Two Jobs.

Everything you need.
Nothing you don't.

Each reference card is a double-sided tool — one side for in-game rule questions, one side for reading the NMJL card. Designed to be consulted in seconds, not studied for minutes.

Side A

In-Game Quick Reference

The rules players get wrong most often, organized for instant scanning. ✓/✗ markers so the answer is visible before you finish reading the header.

  • Joker usage rules
  • Joker swap mechanics
  • Calling a discard tile
  • Dead hand causes
  • Charleston basics
  • Winning call rules
  • Turn order after a call
  • Simultaneous call resolution
Side B

NMJL Card Decoder

How to read the annual National Mah Jongg League card — the most common source of confusion for new and intermediate players.

  • Color coding by suit
  • Set types: Pair, Pung, Kong, Quint
  • Parenthetical notations (any, like, consecutive, same)
  • Exposure rules: open vs. concealed
  • Tile count per hand
  • F / W / D notation (Flower, Wind, Dragon)
Side A · In-Game Rules

The rules that
trip everyone up.

These are the six moments every game produces — the pause, the question, the table discussion that breaks the rhythm. The quick reference card resolves them in seconds.

Jokers
✓Sets of 3 or more only (Pung, Kong, Quint)
✓Swap from an exposed set — replace with exact tile, your turn only
✗Never in a pair
✗Never as a single tile
Calling a Tile
✓Call a discard to complete an exposed set
→Calling skips turn order from discarder to you
✗Cannot call for a pair
✗Cannot call for a single tile
Dead Hand
→Hand is dead if it can no longer be legally completed
→You stay in the round — you cannot win
✗Illegal call
✗Accidental tile exposure
✗Wrong tile count
The Charleston
→Pass 3 tiles: right → across → left
✓Blind pass on across only
→Second Charleston requires all players to agree
Winning
✓Exact match to one hand on the card
✗No Jokers in pairs or singles
✗Wrong call = dead hand
Two Players Call
→Closest player to discarder's left wins
✓Mahjong call always wins, regardless of position
→Other caller simply missed — no penalty
Side B · NMJL Card Decoder

How to read
the card.

The NMJL card releases annually. Here's what every notation means — so interpreting a hand takes seconds, not a rules discussion.

Suit Colors

Red Craks (characters with red center)
Green Bams (bamboo)
Blue Dots (circles)
Black Winds and Dragons
F Flower tile [verify current card notation]
W / D Wind tile / Dragon tile [verify notation]

Set Types

Pair 2 identical tiles. No Jokers allowed.
Pung 3 identical tiles. Jokers may substitute.
Kong 4 identical tiles. Jokers may substitute.
Quint 5 identical tiles. Requires at least one Joker.

Parenthetical Notations

(any) Any one suit — your choice. Commit and stay consistent.
(like) Same number, different suits.
(consec) Sequential numbers within one suit (e.g., 3-4-5 Bams).
(same) All tiles identical — same number, same suit.

Exposure Rules

Exposed Set placed face-up after calling a discard. Others can see it.
Concealed Set stays hidden until Mahjong. Cannot be completed by calling a discard.
Brackets [ ] Indicates concealed set on the card. [verify notation]
Tile Count Every complete hand = exactly 14 tiles.
Get the Cards

One per player.
At every table.

Reference cards are included with the full Otto set and available separately. Join the waitlist to be notified when presale opens.

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