The Mah-Jongg Key

Alchemy is the whole conceit here: sulphur, mercury, salt and the phases of the moon sit where bamboo sticks and character suits normally go, and because none of those marks carry a number, you end up sorting the board by shape alone.

Removal follows the usual open-tile rule, a piece lifts only when nothing rests on top of it and one side is clear, but the special ranks bend that. Red tiles, green tiles and moon-phase tiles pair with any other tile of the same type, so a stray crescent can unpick a stack that had run out of honest matches. The Titans pile builds the layers into another arrangement.

Nothing is timed, and a hint sits ready for the moment the layout stops speaking to you. Those two together make the alchemy set a board you can sit over for twenty minutes without losing anything by it. Another layout to unstack is Safari Story.

The original is a 2006 Flash release and it plays on this page through the Ruffle emulator rather than the plug-in it was written for. That shows: the chime on a matched pair sometimes arrives late, tile animation can run a shade fast, and full screen comes from the browser rather than from a button inside the game. For one more pile of the same kind, see Yummy Food Mahjong.

1. Look for a tile with a clear left or right edge and nothing stacked above it.
2. Find the same alchemical mark elsewhere on the board and click both pieces to lift them.
3. Treat the red, green and moon-phase ranks as wild within their own group: any red goes with any red.
4. Ask for a hint when the layout looks locked, then keep working outward from the stack it points to.

• Save the crescents — moon-phase pieces pair freely with each other, so they are the cheapest way out of a dead stack.
• Strip the crown first — the top of the alchemy pile pins four faces at once.
• Learn three marks properly — sulphur, mercury and salt look alike at a glance and cost most of the wasted clicks.
• Use full screen for the small glyphs — the etched symbols lose their detail badly at window size.
• Take the untimed board slowly — nothing punishes a long look before the first pair.