# Are mahjong solitaire boards always solvable? > Most mahjong deals are shuffled at random, and a real share of those cannot be won at all. Here is how a board is made solvable, and how to tell. Source: https://apps.swtlm.com/blog/are-mahjong-solitaire-boards-always-solvable · TLM Apps — focused mobile apps from a team of engineers. Published: 2026-07-24 · Updated: 2026-07-24 · TLM Software Design No — not if the tiles were dealt at random, which is how most mahjong solitaire games do it. A randomly dealt board can have no winning sequence at all, so a game you lost may have been unwinnable before you touched it. A board can be *made* solvable, but only by choosing the faces as a playthrough is simulated rather than scattering them first, and that is a deliberate choice a studio has to make. ## Why a random deal can be dead on arrival Mahjong solitaire has one rule that creates the problem. A tile is *free* only when nothing sits on top of it and at least one of its left or right neighbours is clear. You can only match two free tiles. So the layout is a dependency graph. Every tile you remove unlocks others, and a pair whose two halves are buried under each other can never be matched: the first one needs the second gone before it comes free, and the second needs the first. Deal the faces onto the layout at random and nothing stops that arrangement happening. One mutually-buried pair is enough to kill a board. That is why solvability belongs to the way a deal is generated and cannot be patched in later, and it is the single hardest thing to get right in the genre. Worth asking about before you install any of the [puzzle games](https://apps.swtlm.com/games) that ship it. Figures circulating for the classic turtle layout put the unsolvable share at a few per cent. That is small, and still often enough to meet regularly if you play every day. We have not measured it ourselves and would rather not quote a number as though we had, because it depends entirely on the layout — a tall, heavily stacked shape buries more tiles than a flat one — and on how the game deals. The qualitative point is the one that matters anyway: with a random deal, some boards cannot be won. ## How a board is made solvable The trick is to stop dealing tiles and start playing a game while you deal. Instead of scattering the faces onto the layout and hoping, the generator simulates a legal playthrough and decides the faces as it goes: 1. Start with every position occupied. 2. Pick any two tiles that are *free right now* under the ordinary rule. 3. Give that pair a face, one that appears nowhere else on the board. 4. Remove them, which frees up others, and repeat until the board is empty. The sequence it picked is a complete winning line, so one provably exists. There is no search and no solver: the guarantee comes from the construction rather than from checking afterwards. The stronger property falls out of one detail. Removing a tile can only free other tiles and never block them, which mathematicians would call a monotone rule. So a pair that was free during the simulation stays free until somebody actually takes it, and a free matching pair therefore exists at every point no matter what order the player picks. The board is not merely winnable along one hidden path. It is winnable along any path. This is how [Midnight Mahjong](https://apps.swtlm.com/mahjong-solitaire) deals a board on its default difficulty. The guarantee is a property of the algorithm rather than a claim in the marketing copy, which is why harder difficulties can simply turn it off and deal at random for anyone who wants the older, riskier game. ## Then why did I still get stuck? Because whatever you were playing was not dealing that way. On a board built by the construction above you cannot get stuck: a free matching pair exists at every point regardless of your choices, so a dead end is proof the deal was random. This is worth knowing when a game offers both. Midnight Mahjong deals a guaranteed board by default and drops the guarantee on its harder settings, so "can I lose here" is a setting rather than a mystery. Its Shuffle button re-deals a guaranteed arrangement either way, which is what makes it a real escape instead of another roll of the dice. Where board management still decides the outcome is in games that deal at random, and in the clock. Two habits help in both: - **Clear from the top and the ends.** Tiles high in the stack block the most other tiles, so freeing them early widens every later choice. - **When four of a face are visible, look before matching.** Ask which pair leaves the other two reachable, rather than which pair is nearest. That is the same instinct a [block puzzle](https://apps.swtlm.com/blog/block-puzzle-strategy-keeping-the-board-open) rewards: the move that scores now is not always the move that keeps your options open. ## Is a shuffle button the same thing? No, and the difference matters when you are choosing a game. A shuffle takes the tiles still on the board and redistributes their faces. It rescues a stuck position, but it usually redistributes at random, so it can hand you another dead one. Some games cap how many shuffles you get. That is a fair way to price a rescue and a poor substitute for a deal that was never broken. A guaranteed deal removes the need for the rescue on the default difficulty. Midnight Mahjong keeps a shuffle for the harder ones, where the deal is random and a dead position is possible, and that shuffle re-deals a guaranteed arrangement instead of another random one. It always gets you out. ## What to look for before you install The claim is cheap to make and expensive to implement, so check where it is made: - **In the settings, as a difficulty or a toggle** — the strongest signal. A studio only builds a control for something the code actually does. - **In the store description, in a specific sentence** — "every deal is solvable" is a claim; "relaxing gameplay" is not. - **Nowhere at all** — assume random. Guaranteeing solvability is the most interesting engineering decision in a mahjong game, and nobody who did it keeps quiet about it. While you are reading that listing, the same page tells you what the game costs you in attention. Midnight Mahjong is free with a banner, an interstitial every third game and an optional rewarded video for a hint; a one-time unlock removes all of it. That is on [its page](https://apps.swtlm.com/mahjong-solitaire) and on its card, before you install — the reasoning behind saying so is in [what a puzzle game subscription costs](https://apps.swtlm.com/blog/what-a-puzzle-game-subscription-costs), and the whole shelf is on the [Games page](https://apps.swtlm.com/games). ## Frequently asked questions **Can a mahjong solitaire board be impossible to finish?** Yes, if the tiles were placed at random. A few per cent of randomly dealt turtle boards are commonly said to have no winning line at all, and you can play one of those perfectly and still lose. A board dealt by construction cannot be one of them. **How do I know whether a game deals solvable boards?** Look for the claim in the store listing or in the game's settings. If it is not stated anywhere, assume the deal is random — a studio that went to the trouble of guaranteeing solvability says so, because it is the most expensive thing in the build. **Does a solvable board mean I cannot lose?** With the construction described here, yes — a free matching pair exists at every point no matter which order you play, because removing a tile can only free others. Getting stuck is therefore proof that the deal was random rather than constructed. **Is a shuffle button the same as a solvable deal?** No. A shuffle rearranges the tiles you have left, usually at random, so it can hand you another dead position. It rescues a stuck board; it does not make the original deal winnable. **Why do some games make solvability optional?** Because a guaranteed board removes real losses, and some players want the risk. Midnight Mahjong ties it to difficulty for exactly that reason — guaranteed by default, random on the harder settings.