Logic Puzzle Glossary

The words puzzle players use, in plain English. Handy when a guide says "look for a hidden single" and you are not sure what that means.

Candidate Sudoku

A number that could still go in a square, given what is already in its row, column and box. Writing small candidates in the corners is called pencil marking.

Naked single Sudoku

A square with only one candidate left. It can be filled straight away.

Hidden single Sudoku

A number that has only one possible square within a row, column or box, even though that square still has other candidates. Scanning for these is usually the fastest way through a puzzle. More in 4 real techniques for solving sudoku faster.

Clue Nonogram

The numbers beside each row and above each column. Each number is a run of filled cells, in order, with at least one empty cell between runs. "3 1" means a run of three, a gap, then a single cell.

Overlap Nonogram

Cells that are filled whichever way a long run is placed. In a row of 10 with a clue of 8, the middle 6 cells must be filled.

Flag Minesweeper

A marker placed on a cell you have proved holds a mine, usually with a right-click or long press.

Chording Minesweeper

Clicking a number that already has the right number of flags around it, which opens all its other neighbours at once. Many versions support it.

1-2-1 pattern Minesweeper

Three numbers 1, 2, 1 in a row along an edge: the mines sit beside the two 1s, and the cell beside the 2 is safe. One of several patterns that remove most guessing, covered in Is Minesweeper luck or skill?

Corner strategy 2048

Keeping your largest tile in one corner for the whole game and building a chain of smaller tiles beside it. The standard way to reach 2048, explained step by step in how to win 2048.

Forced move General

A move that the rules or the position leave no choice about. Finding them first narrows every puzzle down.