Mahjong

The tiles are stacked in layers. Your job is to remove them all, two at a time, by matching identical pairs — but only free tiles may be picked up. A tile is free when nothing rests on top of it and at least one of its long sides, left or right, is open. Click one free tile, then its twin, and both leave the board. That is the whole engine of the game; everything else is judgement.

The tile set is the traditional one: three suits — characters, bamboo, and circles — numbered one through nine, plus four winds, three dragons, and the ornamental flowers and seasons. Suit, wind, and dragon tiles match only their exact duplicates. The four flowers are a family: any flower matches any flower, and likewise any season matches any season. Each tile carries a small printed label in its corner — B3 for bamboo three, E for the east wind — so you never have to squint at the engraving to be sure.

One promise worth repeating: every deal here can be cleared. We build each board backwards, placing pairs the way a winning player would remove them, so a solution always exists. If you reach a dead end, that's the order of play, not the deal — undo a few moves, or shuffle the remaining tiles and continue.

A short history

The tiles come from mahjong proper, the four-player Chinese table game that swept America's living rooms in the 1920s, complete with sets in lacquered boxes. The solitaire version is younger than it looks: in 1981 a programmer named Brodie Lockard built a one-player tile-matching game on PLATO, a pioneering university computer network, laying tiles out in the now-famous turtle shape. Activision's 1986 adaptation, and the version bundled with office computers in the 1990s, made the solitaire form more familiar to most Americans than the table game it borrowed its tiles from. The turtle endures because it is honest: broad, layered, and just deep enough to punish greed.

Advice that actually helps

• Work high and long first. Tiles on the upper layers and in the long middle rows block the most neighbours. Given a choice of matches, take the one that frees more of the board.
• When three copies are visible, pause. Any tile appears four times. If three are free or nearly free, match the two whose removal opens the most — the wrong pairing can wall off the third copy's partner.
• Watch for stacked twins. An identical tile sitting directly on its partner is quiet trouble: they can never pair with each other while stacked, so you must free one of the other two copies. Spot this early, not late.
• Keep both ends moving. The turtle's left and right wings each gate a long row. Nibbling evenly from both sides keeps side tiles becoming free at a steady rate; stripping one wing bare often leaves the other locked.
• Use hints as a nudge, not a chauffeur. The hint shows a legal pair, not the best one. When it surprises you, ask why you missed it — usually a whole region has slipped your attention.

Common mistakes

The classic error is matching every pair the moment it appears. Matches spent on tiles that were not blocking anything are moves the endgame will bill you for. The second is ignoring the third dimension: a tile that looks reachable may be pinned from above two layers up, and the tall central stack is always the last to argue. The third is refusing the undo button out of pride. This is a game of information — every move you take back returns knowing more about the board than you did the first time. The tiles do not judge. Neither do we.