You may call a discarded natural tile to complete a single or pair when it immediately completes your entire legal mahjong hand. You cannot call it simply to improve an unfinished single or pair while continuing to play.
This distinction prompted a Reddit question about calling a single West for mahjong. The player was pursuing a concealed hand and wanted to know whether the final West could come from a discard. Their post referred to an older card, so the lesson is the claim rule, not whether that old hand appears on today’s card.
Ask whether the whole hand is finished
The AMJA guide to winning on a discard explains that a claimed winning natural tile may complete a single or pair, among other groupings.
Before calling, check your complete hand against one line of the card your group uses. Account for all fourteen tiles, the required suits, the specified groupings, and the accompanying conditions. A completed pair does not by itself establish a completed hand.
| Your situation | Can you claim for that purpose? |
|---|---|
| The discard completes a pair but other tiles are still missing | No |
| The discard completes the pair and your entire legal hand | Yes, for immediate mahjong |
| The discard fills a single and completes the entire legal hand | Yes, for immediate mahjong |
What changes for a concealed hand?
The AMJA rules overview states that concealed hands may call the final tile for mahjong. Calling that winning tile is different from making an earlier exposure and continuing to play.
Read the concealed condition before you commit to an exposure. If you have already exposed tiles during play, adding the missing tile does not undo the earlier action.
A practice check with a partner
Choose a complete legal hand from the card you own and build it face up for a teaching exercise. Remove one tile from a pair. Ask your partner to explain why the missing natural tile could be called for a win.
Next remove an additional tile elsewhere. Ask the same question again. The pair would still become complete, but the entire hand would remain unfinished. Comparing the two layouts makes the final-tile condition easier to see.
Repeat with a single position. Keep the exercise separate from a normal dealt game and check the complete line each time.
A natural tile and a joker are different questions
A discarded joker cannot be taken as the winning tile. Also, a joker cannot represent the missing natural tile in a single or pair. The AMJA joker restriction explains that rule.
For a broader practice routine, see our beginner card-reading guide. You can rehearse with your existing tiles, including decorative sets such as Elves & Festive Christmas set, once everyone recognizes the faces.