No-guess Minesweeper

What does no-guess mean?

An ordinary random board can force a 50/50: two tiles, one mine, and no clue anywhere that tells them apart. A no-guess board has a route from its opening to every safe tile using deductions only. You can still lose to a wrong move or a misplaced flag, but never to a coin flip the board forced on you.

How a no-guess board is made

1. You choose your opening. The game prepares the mine layout around that tap, keeping it and its neighbours clear.
2. A solver checks it. It plays the board the way a careful player would, using only revealed clues and deductions, and tests whether every safe tile can be cleared.
3. You play the checked board. If the solver gets stuck, that layout is not used. What you get is a board with no forced guess.

What no-guess does not mean

It does not mean every tile can be decided right away. Sometimes the clue you need is on another part of the board, and you have to open more of it first. It does not protect you from your own flags either: a wrong flag makes a later chord open a mine.

Stuck does not always mean guessing

When a no-guess board seems stuck, the answer is there; it is usually one of these:

• Subtract proven flags from every number they touch. A 2–3–2 above a flag is really a 1–2–1. See the worked example.
• Compare overlapping numbers. Two clues that share most of their neighbours often settle the tiles they don’t share. 1–1 and 1–2 are the basic cases.
• Count the whole board near the end. If the mines left equal the mines one clue still needs, every other hidden tile is safe. Endgame counting.
• Look elsewhere. A different edge of the opening may be easier to push forward.

Why no-guess boards cap the mines

The denser a board, the more often a random layout forces a guess, and the longer a generator has to search for one that doesn’t. So no-guess games cap how dense a board can get. That cap is a design choice that balances difficulty against waiting time, not a mathematical limit on Minesweeper.

No-guess in our games