🔥 Hard logic puzzles
4 categories · 4×4 and 4×5 · for teens and adults
Hard logic puzzles are the real challenge: four categories, five items in each and six grids that connect to each other. The clues are short, but every single one is needed: there are no extra clues here.
In a hard puzzle most of the work is connecting the grids: once there is a ✓ between two items, everything you know about one is true for the other. Clues like “live next door” or “exactly one year apart” narrow each one to two options.
Sometimes you need an advanced step: assume a cell is ✓, keep reasoning, and reach a contradiction. Then the cell must be ✗. That kind of step also shows up in the Hint explanation.
Want something a bit calmer? There is a medium level (4×4) here too.
Questions and answers
How long does a hard puzzle take?
Between 10 and 30 minutes for most solvers. Work in order: direct clues first, then links between grids, and the order clues last.
Can the hard puzzles be solved without guessing?
Yes. Every puzzle is checked by a computer solver that works step by step with logic, and a hard puzzle needs at most two assumptions that lead to a contradiction.
What does “but not both” mean?
In an “either… or…” clue exactly one of the two parts is true. For example: “Either Zoe ate pizza, or Zoe arrived at 12:30 (but not both)”, so whoever ate pizza did not arrive at 12:30.