Didn't Do It · 29 August 2026 · 6 min read

How to solve a deduction puzzle without guessing

Lees in het Nederlands

A good deduction puzzle never asks you to be lucky. It hands you enough true statements to remove every wrong answer, and the only question is whether you turn that information into a calm process or a frantic scan. This is the process.

a chain of clues narrowing a fieldA CHAIN OF CLUES NARROWING A FIELD250the grid120clue 158clue 227clue 312clue 45clue 51the culprit

The shape of every elimination puzzle

Whatever the theme, an elimination puzzle has the same skeleton: a field of candidates, a set of true statements about the answer, and the promise that applying all of them leaves exactly one. Nothing in a fair puzzle contradicts anything else, and nothing is hidden. If you are stuck, the missing piece is in the clues you already have.

In Didn't Do It that field is a grid of names and the statements are worded as innocence: every clue describes the culprit, so every name it does not describe is out. The wording matters less than the habit — read a clue as a filter you apply by hand, not as a riddle to interpret.

a chain of clues narrowing a fieldA CHAIN OF CLUES NARROWING A FIELD250the grid120clue 158clue 227clue 312clue 45clue 51the culprit
A chain of five clues walking a grid of 250 down to one name. Each step is a decision you make, not one the game makes for you.

Step one: find the clue that cuts deepest

Clue numbers are labels, not instructions. Before you cross out anything, read all of them and ask which one removes the largest group. A distinctive first letter, an unusual surname feature or a position in the grid usually beats a clue about counting vowels — not because it is more true, but because it is faster to apply to fifty names.

Cutting deep first is not just about saving effort. A smaller field makes every later clue easier to apply accurately, and accuracy is where puzzles are actually won.

A rule of thumb: if a clue does not remove at least a quarter of what is standing, it is probably not your opening move.

Step two: switch from clues to candidates

Once the field is small, stop working clue by clue. Read one name, compare it against everything you know, and decide. Working clue by clue means re-reading the whole grid once per clue; working name by name means reading each name once.

  1. Pick a name that is still standing.
  2. Walk your clues in the order you find easiest to check.
  3. Cross the name out the moment one clue proves it innocent — there is no need to check the rest.
  4. If it survives every clue, leave it and move on. It is a finalist.

Step three: slow down for anything you have to count

Vowels, repeated letters, doubled letters and name lengths are powerful clues precisely because they are easy to get wrong. Separate the first name from the surname, count deliberately, and check anything that felt close before you act on it.

Ten careful seconds cost less than rebuilding a grid because you crossed out the culprit. See counting clues for the specific traps.

Step four: use the guarantee as a checksum

Exactly one candidate survives a fair chain. That turns the end of a puzzle into a self-check rather than a leap of faith:

Neither of the first two is failure. They are precise feedback about where to look, which is more than most puzzles give you.

Step five: stop optimising for speed you do not have yet

Speed in these puzzles is a by-product of accuracy, not a separate skill. Players who chase the clock start crossing out on impression rather than proof, spend a minute finding the mistake, and finish slower than the careful version of themselves.

Get to reliably correct first. The speed arrives on its own once you stop rebuilding grids — more on that in being fast without being wrong.

Try the method on a case

Related reading