How to Solve a Logic Puzzle

If you're new to grid-based logic puzzles, this tutorial will teach you the basics. Start with the "Introduction" first, then move on to the tutorials discussing specific clues or solving methods. Each tutorial contains a number of different slides - you can advance to the next slide by clicking "Next slide" at the bottom of each page, or by using the circled numerical links below each slide. Choose your specific tutorial from the list below to get started.


  • Introduction
  • True and False Clues
  • Multi-Elimination Clues
  • Neither/Nor Clues
  • Either/Or Clues
  • Greater/Lesser Than Clues
  • Unaligned Pair Clues
  • Transpositions
  • Parallel Cross Eliminations
  • Skewed Cross Eliminations
  • Pseudo-True Pairs (Aligned)
  • Pseudo-True Pairs (Staggered)
  • Transitive Relationships (Either/Or)
  • Transitive Relationships (Unaligned Pair)
  • Comparative Relationships
  • Trial and Error
  • Taking Notes

  • Skewed Cross Eliminations


    • Slide #1

      Skewed cross eliminations are really not much different from parallel cross eliminations... they're just harder to spot. The basic logic is the same: If A can only be X, Y or Z, and B cannot be X, Y or Z, then A cannot be equal to B.

      We'll use this grid to illustrate a few cross elimination examples.



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    • Slide #2

      Take a look at the "Sierra" column, shaded in yellow.

      The current grid layout shows that Sierra can only be Theros or Xidat, since Heang, Nyeos and Zenmoto have all been eliminated as possibilities.



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    • Slide #3

      Now compare the "Sierra" column (yellow) to the "March" row (green).

      The green row shows that March cannot be Nyeos, Theros or Xidat. This, along with the information we gleaned from the yellow column, gives us a "skewed cross elimination." Do you see where?



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    • Slide #4

      If you didn't see it immediately, don't feel bad - these are hard to spot!

      Take the false relationships from the green row and compare them to the remaining open possibilities for the yellow column. Just as in a "parallel cross elimination", if you overlay the data in the yellow subcolumn with the data in the green subrow, you'll see that all five options are X'd out.



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    • Slide #5

      If the only remaining possibilities for A are all eliminated in B, then A cannot equal B.

      Therefore, since Sierra can only be Theros or Xidat, and March cannot be either Theros or Xidat, Sierra cannot be equal to March. We can mark a false relationship where Sierra and March intersect.



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    • Slide #6

      There remains one more "skewed cross elimination" in this grid.

      Can you find it?



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    • Slide #7

      The grid shows that January can only be Sierra, X-ray or Zulu. It also shows that Dillard cannot be Sierra, Dillard cannot be X-ray, and Dillard cannot be Zulu.

      Therefore, since all remaining possibilities for January have been eliminated for Dillard, Dillard cannot equal January.



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