Flagdoku
Balance flags with Minesweeper-style clues
Flagdoku blends Sudoku-style region constraints with Minesweeper clues. Place flags so every row, column, and region has exactly three flags, and each numbered cell is surrounded by the correct count.
Rules
Each row and column must contain exactly three flags—no more, no less.
Each block (region) must also contain exactly three flags, just like rows and columns.
Numbers show how many flags are in the eight surrounding cells. Use them to deduce where flags and empty cells must go.
You can mark cells as empty to track safe squares. Empty marks aren’t required to win, but they help reduce mistakes.
Strategies & Tips
Start with 0s and High Numbers
A 0 means all surrounding cells are empty. High numbers (like 6–8) nearly fill the neighbors with flags, making them easy to resolve.
Use the 3-Flag Rule
If a row, column, or region already has three flags, every remaining cell there must be empty. If it needs exactly three more, all remaining cells are flags.
Cross-Check Clues
A single cell affects row, column, region, and multiple clue numbers. Look for cells that satisfy multiple constraints at once.
Clear Around Solved Clues
When a clue is satisfied, mark the remaining adjacent cells empty. This creates space for other deductions.