Flagging certain mines

Level: Basic

If the closed-neighbor count equals the number, they're all mines.

If the 'number of still-closed cells' around an open number cell exactly equals that number, then those closed cells are all confirmed mines.

For example, if a cell showing 3 has exactly three closed neighbors, all three are mines. Flag them, and the deductions that follow become much easier.

This is the first confirmation technique to try. Each flag you place lowers the 'remaining mine count' for the adjacent numbers, which often triggers a chain of new confirmations.

Related techniques