How to solve logic grid puzzles
Mark × for every pair a clue rules out and ● for every pair that goes together. When a row has one open square left, it’s a ●.
- Ada doesn’t own the beagle.
- Ben doesn’t own the beagle.
- Cora adopted in 2020.
- The poodle owner adopted in 2019.
- Ben didn’t adopt in 2021.
How it works
A logic grid puzzle gives you a few people, a few categories of things, and a list of clues. Each person has exactly one item from every category, and no two people share one. Your job is to find every match.
The grid has a block for every pair of categories. Each square asks one question: do these two go together? Mark × when a clue says no and ● when it says yes. Every row and every column of a block ends up with exactly one ●.
Two moves do most of the work. When a row or column of a block has one open square left, that square is ●. And when you place a ●, the two items belong to the same person, so anything you know about one is true of the other. That second move is called transfer.
The order that works
Read every clue once and mark the plain facts first: every “is” gets a ●, every “isn’t” gets a ×. Then scan each block for rows and columns with one open square.
After every ●, look along both items’ rows in the other blocks and copy what you find. Most stuck moments end the moment you do this.
Leave the clues that compare or give options for later. They get much easier once a few squares are settled. Cross each clue off when it has nothing left to tell you.
When you get stuck
Pick a clue with two options, like “Ada owns the beagle or the poodle”, and check each option against the grid. If one leads to a clash, the other is true. And look for a person whose open choices in one category all share a ×: that × is true for the person too.
Worth memorizing
Every block row and column gets exactly one ●.
When only one square is open, it’s the ●.
A ● joins two items into one person.
Copy every × and ● between their rows.
Plain facts first, comparisons later.
Cross off each clue once it’s used up.
Practice
0 of 4 rightClues 1 and 2 are marked. Who owns the beagle?
Cora owns the beagle and adopted in 2020. Which year goes with the beagle?
Clue 5 says Ben didn’t adopt in 2021. Which year did Ben adopt in?
How many ● does this grid have when it is solved?