Technique 5 of 8 · Simplifying clues
Read the mines a number still needs
The guide and all minesweeper techniques
Minesweeper techniques
- 1Finding certain minesStart here
- 2Finding safe cellsStart here
- 3Flagging and chordingCore technique
- 4Comparing neighbouring numbersShared cells
- 5Subtracting known minesSimplifying clues
- 6The 1–2–1 patternRecognising patterns
- 7The 1–2–2–1 patternRecognising patterns
- 8Using the remaining mine countFinishing a board
A revealed 3 with one proved mine beside it still needs two mines among its other covered neighbours. The displayed number stays 3; it is your working count that becomes two.
Do this separately for each clue. A flag only reduces numbers it actually touches, and a flag that has not been proved should not enter the calculation.
Example 1: Turn 2–3–2 into smaller requirements
Step 1 of 3
The proved flag touches the 2, the 3 and the other 2. Subtract one from each.
The bottom-middle flag touches all three middle-row clues. Each therefore has one mine already accounted for.
Their remaining requirements are 1, 2 and 1. Compare the left remaining 1 with the middle remaining 2: the top-right cell must supply the extra mine. Comparing from the other side proves the top-left mine, leaving the middle cell safe.
Work inside the solid frame. Every possible mine neighbour of these clues is inside it. Cells beyond the frame are background, not revealed zeros or extra clues.
Flags are proved mines. A tick marks a cell proved safe; its number is not shown.
Blue-ringed numbers are the clues to compare. Shading marks the cells being discussed.
Try it yourself
Try the reasoning yourself. Choose an answer to see the explanation.
The left-middle flag was proved earlier. Subtract it from the three numbers in the middle column, then compare their remaining groups.
Practice only: no clock, saved game or hint charge.
Task 1 of 2: Flag both cells that supply the remaining mines.
Choose a cell on the board.
Work inside the solid frame. Every possible mine neighbour of these clues is inside it. Cells beyond the frame are background, not revealed zeros or extra clues.
Practice close-up: rows 1–4, columns 1–4.
Flags are proved mines. A tick marks a cell proved safe; its number is not shown.
How to spot it faster
- Read a clue as remaining mines among remaining possible cells.
- Count only proved flags that touch that particular clue.
- Write the smaller requirements in your reasoning; do not imagine the displayed numbers have changed.
Common mistakes
Subtracting a nearby flag that does not touch
A mine two cells away does not belong to this number's count. Follow the eight-neighbour rule for every subtraction.
Subtracting the same flag twice
One flag contributes one mine to each number it touches. It never reduces a single clue by two.
Questions
Further reading
Try it
Find a number beside a proved flag in solo play. Say how many additional mines it needs, then compare that reduced requirement with its neighbours.
Play solo Minesweeper