How to solve logic grid puzzles

Five people, five jobs, five cities, and a list of clues. The grid does the remembering so you can do the reasoning.

You are matching items from several categories, one-to-one, using clues that constrain the pairings. The grid is not decoration — it is the whole method.

Mark exclusions, not just matches

This is where beginners lose. A clue saying "Anna is not the doctor" feels like it tells you nothing, so it goes unrecorded. It tells you a great deal: cross that cell, and when four of five cells in Anna's row are crossed, the fifth is confirmed with no further clue needed.

Most of a logic puzzle is solved by accumulated exclusions, not by direct statements.

One tick clears a row and a column

Because the matching is one-to-one, confirming Anna is the teacher means nobody else is the teacher and Anna is nothing else. Every tick should be followed immediately by crossing out the rest of its row and column. Skipping this is the commonest way to stall on a puzzle that was already solved.

Chain across categories

The step that unlocks hard puzzles: if the doctor lives in Lisbon, and Anna is not in Lisbon, then Anna is not the doctor — even though no clue mentions Anna and the doctor together. Deductions travel through a shared category.

Negative clues are strong

"The teacher is not the youngest" and "Bruno is not the teacher" combine to place real constraints, and clues of the form "X is either P or Q" are worth translating into crosses against everything else immediately.

Frequently asked questions

Do I need to guess?

No. Every puzzle has a single solution reachable by pure deduction.

Why record things that are ruled out?

Because eliminations are how most of the puzzle is actually solved. When every option but one in a row is crossed, the remaining one is confirmed without any clue saying so directly.

What if two clues seem to contradict?

One has been misread — commonly an 'or' treated as an 'and', or a comparative like 'older than' applied backwards. Re-read both before assuming the puzzle is at fault.