All-Different Clues in Logic Grid Puzzles
Part 5 of 6 of How to Solve Logic Grid Puzzles.
An all-different clue lists several things and tells you that no two of them are the same. It is a bundle of false clues in one sentence. You may also see these called multi-elimination clues.
Clue 6. The five butterflies were the butterfly that was auctioned 3rd, the insect that sold for $260, the butterfly that sold for $270, the butterfly that sold for $280 and the butterfly won by Harry.
The puzzle has five butterflies and the list has five entries, so each entry is a different butterfly:
- the 3rd lot
- the $260 butterfly
- the $270 butterfly
- the $280 butterfly
- Harry's butterfly
Cross out every pair
Take the entries two at a time. Wherever two of them meet on the grid, put an X.
Start with Harry. His butterfly is none of the other four, so it wasn't the 3rd lot, and it didn't sell for $260, $270 or $280.
Next, the 3rd lot. It is none of the three priced butterflies, so it didn't sell for $260, $270 or $280. The $280 square already has its X, from clue 2.
That leaves the three prices. They are in the same category, so they share no squares and there is nothing to mark between them.
Don't miss any
Work through the list in order: the first entry against each of the others, then the second against the rest, and so on. Skip any two entries from the same category.
These clues are easiest to mark on an empty grid, where the pattern of X's is clear, so many solvers do them first.
The two-item version
A clue such as "The 6th lot and Kelly's butterfly are different butterflies" is the same idea with a list of two. It is a false clue in other words: put one X where 6th meets Kelly.
Next: Finishing the grid
Previous: Pair clues
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