Currently, it looks like our next fortnightly topic challenge is going to be about puzzles that I have tentatively called "grid logic" puzzles. A more precise definition would be "abstract puzzles on a grid using a pure logical deduction to arrive at an answer. The answer is a modified version of the original grid satisfying specific properties given by the rules of that specific instance that relate to relative placement of 'objects' (typically either numbers, bars, geometric shapes, or shading squares)."

However, the hypothetical tag is extremely similar to the current tag , which refers to puzzles with clues like "The Belgian man lives to the left of the person who owns a fish".

So, what tag name should we use for these puzzles? They all share the idea of "logical deductions, usually on a grid", but there are very distinct examples:

  • Masyu, in which you have to draw a loop connecting all the circles according to specific rules

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  • LITS, in which 4 squares have to be shaded in each region to make a tetromino so no two of the same tetromino are touching and no 2×2 squares are formed

enter image description here

  • Akari, in which "lightbulbs" acting like chess rooks must light up the whole grid without attacking each other

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  • Shakashaka, in which triangles must be added to a grid to make all unshaded areas rectangular

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  • Fillomino, in which a grid must be divided into regions so each number is in a region of its own area, and no two equal-area regions touch

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  • and many, many more.

What concise phrasing could we use to describe all of these?

All example puzzles here were made by Mathgrant, a writer for GMPuzzles. For more puzzles in this genre, I recommend GMPuzzles, Nikoli, and Krazydad.

  • $\begingroup$ I think we need a better description of the kind of puzzles you're talking about. "Logical deduction, usually on a grid" sounds very broad, and giving a few examples and then saying "and many, many more" isn't giving me a good idea of the common theme. (I downvoted this proposal on the topic challenge thread precisely for this reason.) $\endgroup$ Commented Jan 7, 2017 at 16:12
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    $\begingroup$ Note that, while we want the tag to be as accurate and descriptive as possible, we do have a tag description and tag wiki that explain exactly what puzzles fall under a given tag's purview. While I agree that we should find the best tag name possible, we don't need to reject ideas on the basis that they could potentially be confused with other tags. $\endgroup$ Commented Jan 7, 2017 at 16:47
  • $\begingroup$ Do you guys think Numberlink ("Flow") is considered "grid deduction"? $\endgroup$ Commented Jan 11, 2017 at 23:22
  • $\begingroup$ @greenturtle3141: Sure! $\endgroup$
    – Deusovi Mod
    Commented Jan 11, 2017 at 23:49

2 Answers 2



As with Rubio's suggestion, we leave out the word logic to avoid confusion with 'logic-grids'.
I feel like this is a bit more descriptive, as what are we doing in these puzzles but deducing the state of a grid? I tried thinking about what these had in common, and really, they are puzzles where we deduce the state of a grid.

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    $\begingroup$ +1 to this. "Deduction" tells the reader what these puzzles are all about - logical deduction - but without using the word "logic" which could be confused with logic-grid. $\endgroup$ Commented Jan 8, 2017 at 12:54


  • Avoid the word "logic" entirely, so it doesn't show up if someone is trying to figure out what tag to use for logic grids.
  • Highlight the grid nature of these puzzles.
  • Call them "challenge" because they're their own end, not a means to arriving at the answer to some deductive mystery.
  • $\begingroup$ But logical deduction is a core part of these. A crossword, for instance, would not be one of these puzzles, since it isn't purely logical deduction. (Oh, and I don't think "challenge" is very descriptive... every puzzle is a challenge, isn't it?) $\endgroup$
    – Deusovi Mod
    Commented Jan 7, 2017 at 16:35

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