Minesweeper Chording: How to Open Safe Neighbors
Chording opens several neighboring squares in one action when the flags around a number match its clue. Learn the rule, see a worked example and practise safely.
What is chording in Minesweeper?
Chording is a shortcut for opening the remaining covered neighbors of a revealed number after you have marked the same number of mines around it. If a 2 has exactly two flagged neighbors, the other covered neighbors can be opened together. The number is ‘satisfied’ because its mine count is accounted for.
The action saves repeated clicks, but it does not verify that your flags are correct. The game checks how many flags surround the clue, not whether those flags are truly on mines. Chording is safe only when both the clue and your confirmed mine positions are correct.
The exact rule before you chord
Count the flags touching the revealed number, including diagonal neighbors. Chord only when that count equals the number. A 1 needs one marked neighbor; a 3 needs three. If the count is lower, the clue still has an unaccounted-for mine. If it is higher, at least one flag must be wrong or the board has been read incorrectly.
A clue checks up to eight surrounding squares. Corners and edges have fewer neighbors, but the same count applies. Covered squares that already have flags are excluded from the opening action; the chord targets the remaining covered, unflagged neighbors.
How chording works on this site
On the Classic game here, click an already-open numbered square to chord it. The game compares the number of adjacent flags with the clue. If they match, it opens the remaining covered neighbors; if they do not, nothing happens. On a touch screen, tap the open number after placing your flags. This does not change the normal reveal and flag controls for covered tiles.
Try the action first on a clue whose neighboring mines you have proved, not merely guessed. You can practise the rule in the interactive lesson on the Practice page without risking a ranked board.
A quick example: a satisfied 1
Imagine an open 1 with one confirmed mine flagged next to it and several other neighbors still covered. Because the clue requires exactly one mine and the flag accounts for it, every other covered neighbor must be safe. Chording opens those neighbors in one move, often revealing new numbers or a blank area.
The important word is confirmed. If the flag is only a guess, the logic is not complete. The game will still chord because it sees one flag, and if that flag is on a safe square it may open the actual mine beside the clue.
Why a wrong flag makes chording dangerous
A chord can open several squares at once, so one incorrect flag can turn a harmless action into an immediate loss. Suppose a 2 is surrounded by two flags, but one flag is actually safe. The game sees two flags and opens every other covered neighbor, including the unflagged mine that the clue still needed.
Before chording, revisit the deductions that placed each flag. Check the clues that touch it, include diagonals, and make sure the number you are satisfying has no other flagged neighbor you overlooked. If you cannot prove the flags, reveal a safer square or continue comparing clues instead.
Chording versus opening one square at a time
Opening neighbors individually gives you more control. It can be useful when a clue has many covered neighbors, when the flags are uncertain, or when you want to inspect the board after each reveal. Chording is most useful when the mine count is exact and you are ready to take all remaining safe neighbors together.
Neither action replaces deduction. Chording does not discover where a mine is; it uses a mine count you have already established. Good players use it to reduce unnecessary clicks after the logic is clear, not to speed past an unresolved clue.
Common chording questions and mistakes
If nothing happens, count the adjacent flags again. A flag one square farther away does not count, and a diagonal flag does. The clue must be open and numbered, and the flag count must match it exactly. Empty squares do not provide a numbered clue to chord.
Do not assume that a visual flag is proof. Flags are markers chosen by the player; only the surrounding numbers can support them. If chording fails because the number of flags does not match, treat that as a useful prompt to review the board rather than adding another flag just to activate the shortcut.
Build a reliable rhythm for chording
A steady routine makes the shortcut easier to use accurately: finish a deduction, place only the flags it proves, count the flags around the satisfied clue, and then chord. After the neighbors open, pause and read the new numbers before marking more mines. This keeps the action connected to the reasoning that justified it.
If the board changes in a way you did not expect, stop and review the flags before continuing. Chording may open several neighbors in one move, but each new number still needs to be interpreted on its own. You can also open safe neighbors one at a time when you want more control; speed is useful only when it does not replace careful counting.
Practise the control before a ranked game
Chording is a control shortcut, so its activation can differ between versions of Minesweeper. Learn how this site responds before relying on it in a fast run: first prove a mine, place its flag, confirm that the clue is satisfied, and try the action on a low-risk group. The Practice lesson provides a controlled example.
If you prefer individual clicks or use a device where tapping an open clue is awkward, reveal safe squares one at a time. The goal is accurate play, not using every shortcut. Keeping a consistent method also makes it easier to notice a misplaced flag before it can affect several covered neighbors.
Common questions
How do you chord in Minesweeper?
Flag the mines you have confirmed around an open number, then click or tap that number when the flag count equals its clue. The remaining covered neighbors open together.
Does chording work if one flag is wrong?
The game may still activate the chord because it checks the number of flags, not their truth. A wrong flag can cause a mine to open, so only chord after confirming the flags with the clues.
Do diagonal flags count for chording?
Yes. Minesweeper clues count all touching squares, including diagonals, so diagonal flags are included in the chord total.
Can I chord on a phone?
On this site, tap an already-open numbered square after placing the matching flags. The same clue-count rule applies on desktop and touch screens.
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