The single rule that decides whether you can select a tile is simple, but new players misread it constantly. Get it wrong and the game feels broken; get it right and the whole board opens up. This guide explains the playable rule, how to read a stack, and the most common mistakes to avoid. For the broader rules, see our Mahjong Solitaire Rules guide.
The Playable Rule
A tile is playable only when both of these are true: (1) no tile sits directly on top of it, and (2) at least one long edge, left or right, is free (no tile touching that side). If either condition fails, the tile is locked and you cannot select it until the blocking tiles are removed.
The Two-Question Check
Before clicking any tile, ask two questions in order. One: “Is anything on top of this?” If yes, stop—the tile is buried. Two: “Is the left OR the right side completely open?” If both sides touch other tiles, stop—the tile is side-locked. Only a tile that passes both questions can be selected. Run this check consciously for your first few games and it becomes reflex.
Worked Examples
- Buried: A tile in the middle of the Turtle dome has tiles stacked above it. Nothing on its sides matters—it is locked until the tiles on top are gone.
- Side-locked: A tile in the middle of a long row (the rows of Great Wall are the extreme case) has nothing on top, but tiles touching both its left and right edges. It is locked until one end of the row opens up. This is why long-row layouts average 8 minutes: most of the row is side-locked for most of the game.
- Fully free: A tile at the end of a row with nothing above it. Both questions pass—click away.
Reading a Stack
On this site, playable tiles glow or lighten when you hover over them. If a tile stays dim, it is blocked. Train your eye to scan in this order: top of the stack first (to find unburied tiles), then the left and right edges (to find free long edges). With a few games of practice, you will read the board at a glance.
Common Mistakes
- Ignoring the stack height and wasting time clicking buried tiles.
- Matching edge pairs too early, locking the row behind them.
- Forgetting that a tile with both long edges covered is unplayable, even with nothing on top.
- Assuming Flowers and Seasons follow different blocking rules—they do not. Only their matching rule is special (any Flower matches any Flower).
Frequently Asked Questions
Why can I not select this tile?
Either a tile is on top of it, or both its left and right long edges are blocked. Clear the blockers first.
How do I tell if a tile is playable?
Hover over it. Playable tiles highlight; unplayable tiles stay dim. You can also use a Hint, which always points to a playable pair.
Want to test your eye? Open the Classic layout—its flat shape makes the playable rule easy to study.