Subtract known mines first
An open number counts mines in all eight neighbouring squares, including diagonals. For each number, subtract only the flags you have justified. An open 2 with one proven mine beside it still needs one mine among its other unopened neighbours.
If the remaining number equals the count of unopened, unflagged neighbours, every one of those neighbours is a mine. If the remaining number is zero, those neighbours are safe. Do not silently treat an uncertain flag as proof: it can make the rest of the board appear consistent while being wrong.
Compare a small group with a larger one
Suppose an open 1 has only two unresolved neighbours, A and B. Another open 1 has exactly A, B and C unresolved. All other neighbours of both numbers are already known safe. These conditions matter: an extra hidden square or an overlooked diagonal would change the deduction.
| Clue | Unresolved squares | Mines required |
|---|---|---|
| First 1 | A, B | 1 |
| Second 1 | A, B, C | 1 |
Which square can you open?
Reveal the deduction
C is safe. A and B already contain the one mine needed by both clues. C therefore cannot contain another. This does not tell you whether A or B is the mine; leave that question open until another clue resolves it.
The same idea works after subtracting proven flags. Compare the remaining groups, rather than the printed numbers alone. You are looking for one group completely contained in another, with the same number of mines still required.
Why opening around a number can lose
Clicking or tapping an open number opens its unflagged neighbours when the count of surrounding flags matches the number. This shortcut is often called chording. BoomWick checks the number of flags, not whether you put them on the correct squares.
For an open 1, a flag on a safe square satisfies that count while leaving the actual mine unflagged. Chording can then open the mine. Before using the shortcut, trace the clue that justified each flag. If a flag was a guess, use another part of the board to test that assumption first.
Right-click or use F on a focused square to flag with a keyboard and mouse. On a phone, switch to Flag mode before tapping an unopened square. Arrow keys move focus; Enter or Space opens a square.
A safe start is not a guaranteed solution
The first opening and its neighbouring squares are protected. The daily Easy field uses a fixed safe opening so everyone starts from the same position for that UTC date. Random games place mines around your chosen safe start.
This protection does not guarantee that all later moves can be deduced. If independent clues no longer distinguish the remaining possibilities, guessing may be necessary. Winning means revealing every safe square; merely placing the correct number of flags does not finish the field.
Choose Easy while learning to compare groups; larger fields scroll within the board on small screens. For a picture puzzle built around overlapping line constraints, continue with the Nonograms overlap guide.
Take it to the game
Found a rule that behaves differently or an example that needs explaining? Report the problem with the game and the steps you tried.