Lesson 17: Mahjong Threat Shapes – 4 Powerful Patterns Every Player Must Spot
Understanding Mahjong Threat Shapes is a core defensive skill. While exposed melds provide clear information, threat shapes are the tiles your opponents don’t show—yet they strongly influence how risky your discards become. When you can spot these shapes early, you stop losing points to sudden wins and start controlling the pace of the game.
For additional context, you can review the Mahjong Reading Tempo lesson on your site. You may also find this article on Wikipedia useful to help you understand more about Mahjong.
1. The Closed Wait Shape (Most Dangerous)
The closed wait is the threat shape that defeats players most often. It forms when an opponent needs the tile between two others, such as:
This shape waits for bamboo 4, which does not appear in their discards and is difficult for you to detect unless you’re paying close attention to their suit tendencies.
Examples of closed waits include:
waiting for circle 7
waiting for character 5.
Why it’s dangerous:
- Opponents often keep it hidden until the very end.
- It’s hard to see because you rarely know what the middle tile is.
- Many efficient hands naturally contain this shape.
2. The Two-Sided Wait (Fast and Flexible)
A two-sided wait forms when the player holds two consecutive tiles, such as:
This shape wins on either bamboo 3 or bamboo 6, making it fast and efficient. When opponents favor one suit heavily in their discards, assume they may be forming two-sided waits in the suits they keep.
Common examples:
You can detect these shapes when:
- Opponents avoid discarding central tiles in a suit.
- They call a chow that positions them near multiple two-sided waits.
3. The Edge Wait (Predictable but Still Risky)
Edge waits occur when a player holds:
or
These are easier to identify because fewer tiles complete them. However, when the round is late and opponents are folding, edge waits become highly effective finishing shapes.
Why you should respect them:
- They appear frequently in fast hands.
- Players often hide them by discarding middle numbers instead.
- A single careless discard into an edge wait can swing the round.
4. Honor Threats (Silent but Powerful)
When an opponent refuses to discard an honor tile—especially Dragons—you must assume it’s part of a threat shape.
For example, if no one has discarded:
by the midpoint of the game, treat red dragon as extremely dangerous.
Honor threat shapes include:
- One-tile wait for a winning honor
- Pungs forming behind the scenes
- Hands that rely on scoring bonuses
These shapes are invisible until it’s too late, so caution is essential.
Summary
Recognizing Mahjong Threat Shapes comes down to spotting what tiles your opponents avoid discarding. Closed waits and two-sided waits represent the fastest early-round threats, while edge waits and honor waits dominate late rounds. When you learn to visualize these shapes, you defend automatically—without guessing, without fear, and without unnecessary point loss.
