# Questions tagged [grid-deduction]

Puzzles such as Sudoku or Kakuro, where the final state of a pre-existing grid must be deduced logically through clues placed within and/or around the grid. Use with the [logical-deduction] tag. For puzzles where you are given a list of clues which can be used to compose a grid to solve them logically, use the [logic-grid] tag instead.

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### Why can't a 1 go in this field

I've moved onto "expert" sudoku's in my app (Sudoku.com on IOS) and whilst I am getting by solving some, others I'm having a hard time with. With this one, I used a hint so the AI could note ...
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### Horological Horrors

This puzzle is part of the Monthly Topic Challenge #6: Is it really that [time] again?. I was visiting my grandfathers workshop one day, when he received a call and had to run out for a bit. He told ...
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### Next step in this Slitherlink puzzle (Honeycomb)

I have applied all of the techniques that I know of, and can't figure out the next logical step. I even turned on the visual clues, but it didn't help. What would be the next move without resorting to ...
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### The Key to the City

This is part 9 of the puzzle series Around the World in Many Days. Each part is solvable on its own. Deаr Puzzling, This is a Skyscrapers puzzle. Each letter represents a unique number between 1 and ...
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### Trust me: you do not want to go down this road with me

Every cell has a digit from 0 to 9 or one of the four operation symbols +, −, ×, and /, signifying addition, subtraction, multiplication, and division respectively. No digit appears more than once in ...
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### How to make gifs showing a puzzle's solution process?

I've been repeatedly asked to turn this into a PSE question, so here goes. Some people may have noticed that, when I answer a grid-deduction question, my answer often includes, as well as a step-by-...
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### "Symmetric" Tetrikabe

This puzzle's theme is inspired by one from Grandmaster Puzzles' "The Art of Puzzles", but the puzzle itself is original. Rules: (Nurikabe section shamelessly stolen from an earlier puzzle ...
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### Kings of Centuries Past

This is part 7 of the puzzle series Around the World in Many Days. Each part is solvable on its own. Deаr Puzzling, This time I have a shingoki puzzle for you. Draw a single loop that passes through ...
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### Who’s in for a Cruising?

This is part 6 of the puzzle series Around the World in Many Days. Each part is solvable on its own. Deаr Puzzling, Looks like I’m getting way behind schedule already. Sorry about that! Time flies ...
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### Boulders in Valleys

This is a "Boulders in Valleys" puzzle (previously called "Balls on Hills"). It's similar to Slitherlink and Corral; your goal is to draw a path along grid cell edges that ...
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### Happy 2023! Another empty Suguru (Tectonic)

Another assignment for the Suguru (Tectonic) fans out there. Fill in a number in each empty square so that: Each block of n squares has the numbers 1..n. Neighbouring squares are not be equal (...
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### Balls in Pockets (Balls on Hills)

This puzzle is a "Balls on Hills" puzzle. It's similar to puzzles like Slitherlink in that your goal is to find a curve given some clues. The intuition behind this puzzle is balls rolling ...
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### How do I transcribe a Masyu into a Google Sheets?

I received some PDF puzzle books for Christmas and have been solving them in a Google Sheets. The basic tools of borders, background colors, and entering numbers work for lots of genres (Nurikabe, ...
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### Balls on Hills - Loop Deduction Puzzle

This puzzle is a loop deduction puzzle, like Slitherlink and Masyu. It is based on the idea of balls rolling down hills - the clues here give the distance that a ball can roll down. The Puzzle ...
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### How many Nonconsecutive Sudoku solutions are there?

Consecutive Sudoku is a variant with the additional rule that orthogonally adjacent numbers are consecutive if and only if there is a dot/bar on the line between them. A Nonconsecutive Sudoku is one ...
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### Right turn only puzzle

Here is a grid with 24 spaces filled with letters. Pick any place to start your travel in the grid taking right turns only. You must get to all remaining 23 spaces but only once. By doing so create a ...
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### From Before Caesar

This is part 4 of the puzzle series Around the World in Many Days. Each part is solvable on its own. Deаr Puzzling, How have you been? I hope you don’t mind me showing up a little early this time ...
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This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door > Alice and ...
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### Unsure how to continue Sudoku solve/apply Y-Wing strategy

I am not new to solving a sudoku board, but I do not have a lot of experience with harder boards and more advanced strategies (I am able to solve a "hard" board in under 10 minutes, on ...
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### PSE Advent Calendar 2022 (Day 18): Light Up the Christmas Tree

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 100 reputation.< Previous Door Next Door > The year ...
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### Help to solve Star Battle puzzle

I've solved a number of Star Battle puzzles, but once in a while some of them seem much harder than others. This has also been noted earlier here. It seems as if I'm missing some technique to be able ...
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### Empty suguru (tectonic) puzzle

Suguru (also knows as Number Blocks or Tectonic), is a popular type of grid-deduction puzzle: In a rectangular grid of squares, the squares are grouped into blocks. As with a sudoku, some squares ...
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### PSE Advent Calendar 2022 (Day 6): Christmas and Squares

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous DoorNext Door > Today's door ...
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This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous DoorNext Door > 'Twas the ...
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### Around the World in Many Days

Deаr Puzzling, How have you been? I am excited to tell you about my new trip. It’s my most ambitious one yet – a full trip around the world! I will definitely keep you posted about my whereabouts. I ...
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### PSE Advent Calendar 2022 (Day 2): Santa’s Magic Knapsack

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door > Have you ...
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### PSE Advent Calendar 2022 (Day 1): A festive Sudoku

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 50 reputation.Next Door > Rules: Normal Sudoku rules ...
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### A logician's Bingo

Mark some cells on the following Bingo board, so that all statements in marked cells are true AND all statements in unmarked cells are false. A Bingo here is a set of five marked cells in a row, ...
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### 0hn0: is this correct deduction?

Starting with: Text: .....9..6 ....3.2.. 6.5....2. .7.6..R.. ...7R.... ..R.R.6.. 5.....5.. ..4..2... .9...1.1. We soon get to this: Text: ...
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### Find the carpets

This room has been filled with carpets, thirty of them. Each has a number inside precisely equal to its area. Find the carpets!
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### Chain Puzzle: Video Games #02 - Fish Is You

This is the second Chain Puzzle in the Video Games series, in which all puzzles are themed around video games of all genres. The answer to this puzzle is a thematic word or phrase. The solver whose ...
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### This new puzzle type needs a name {7}

This puzzle is part of the Monthly Topic Challenge #5: On-and-onograms - and also extends the 'This new puzzle type needs a name' series... I believe I have invented a new type of puzzle... What is ...
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### Stuck on hard Kakuro

I‘m stuck on this Kakuro. Does anyone have any hints how to proceed? Thanks!
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### Make a wide rectangle out of T-Pipes without loops

Inspired by Pipes. This is a T-Pipe A T-Pipe connects to 3 adjacent cells. This is a 2x2 square containing only T-Pipes. I call the square above is a valid arrangement, because it fulfills the ...
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### Question about a minorly used tag

There once were sixteen chairs. Next to orthogonal. There are people wearing only black or only white. [REDACTED] A black-wearer is in the corner. A white-wearer is next to a black-wearer. At least ...
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### The woefully underclued crossword

This puzzle is part of the Monthly Topic Challenge #4: Cross-*non*-words Giving clues for everything makes things way too simple. In this crossword, four clues are not given and you must find a way ...
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### The p of ps - grid puzzle

Please fill in all boxes with letters. (And what is the p of ps?)
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### Crossword by name, crossword by nature

This puzzle is part of the Monthly Topic Challenge #4: Cross-*non*-words Here's a crossword puzzle - in fact, here are two of them - with a twist. Every entry in the two grids below contains the 5-...
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### Polybius cipher meets Grid Puzzle

Here is a puzzle I've been trying to solve for a week, but I've not made any real progress. Some of the things I've tried I will include as spoilers. The puzzle is from a competition which has just ...
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### Filling a 5x5 grid with {0,1,2} such that each diagonal contains the same elements typewise [closed]

Technothlon 2018 Hauts Section, Q17: Consider arrays of integers, a(ij) with the following property. For all pairs of distinct rows il,i2 and distinct columns jl,j2 the diagonal sum asil,jl)+a(i2,j2) ...
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### The Universe's Secret

To find the universe's secret, first solve the Sudoku variant with #s 1-7 only. No number may be repeated on any diagonal. No numbers go in the squares with red or green dots. Then use the solution ...
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### Sudoku pairs diagonal corners

Is it correct to deduct that the [4,8] (blue) pairs in diagonal corners, project [4,8] on the opposite (green) corners, such that the other values (1 and 6) could be eliminated? (*) I'm not sure if ...
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### 5×5 sudoku with special properties

Complete the network with numbers from 1 to 5 so that the same number does not occur in any line, column, specially marked figure and on both diagonals. I tried to start with a number that I know for ...
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### Tentai Show: Unlikely travels

My friend loves telling me her increasingly outlandish travel stories but I think this time she's gone a little too far and I'm not buying it. Can you tell which faraway land she wants me to think she ...
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### - Pandora's Box -

After Prometheus had stolen fire from heaven and bestowed it upon mortals, Zeus, the king of the gods, determined to counteract this blessing. Zeus commissioned Hephaestus, the god of fire, to fashion ...
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This is a Heyacrazy* puzzle. The rules are as follows: Shade in some cells in the grid. Two shaded cells cannot share an edge, and all unshaded cells must be orthogonally connected. Once finished, it ...
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Seems like this month's topic is not getting enough attention. Here is a simple puzzle to revive the challenge. This 'mess' is hiding some words/phrases. Find them all. .. and, what do they all ...
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### How many solutions in this Statue Park (Loop)?

Rules of Statue Park (Loop), from GM Puzzles Place each of the twelve pentominoes into the grid once, with rotations and reflections allowed. No two pentominoes can overlap or be orthogonally ...
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### This new puzzle type needs a name {OVERLAPPED EDITION}

This is my contribution to the 'This new puzzle type needs a name' series, started by @Stiv. I believe I have invented a new type of puzzle... What is its name? Penpa+ link A little advice.. Even ...
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