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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. 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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My God, it's full of stars!

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids My dear friend, unknown to us, may have relocated again. He sent me imagery and constellation maps indicating that a distant red ...
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Empty sudoku puzzle

The rules are the same as for a normal sudoku puzzle. The only thing different is that instead of numbers for clues, you have greater than/less than (> <) signs between the cells. Have fun solving!...
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Happy Pi-Day! Try to solve this “PiDoku”

To celebrate the Pi-Day (3/14) adequately, a challenging math puzzle must not be missing. Rules: Fill in the numbers 1-9 exactly once in every row, column, and region. On top of that, you need to ...
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Gerrymandering Puzzle - Rig the Election

The following graphic is a map of the country Mathlandia: You are currently running for reelection, but the polls aren't exactly in your favor. Each square in this grid is a county. Counties with a ...
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R.H.P.C. crossword puzzle

This is an entry into the Fortnightly Topic Challenge #36 I got a ticket to the Red Herring Puzzle Club in the middle of the street. There was just a guy giving them out, like some advertisement ...
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Desert Irrigation Project

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids My dear friend researches and designs canal irrigation systems in a remote desert. He's been missing for two weeks. Members of ...
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The Ludicrous Loop: over a thousand cells of circular logic!

Flavourtext is for flavour only. Ladies and Gentlemen, are you feeling ludicrous today? A little loopy, perhaps? Then come one, come all, for I have just the thing for you. Lampreys and Jellyfish, ...
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Who am I??? Wait, isn't this a sudoku?

Jmw jrr qtlf tv ee M6SXr rro tr kz r tyr. Can you find out who I am? Hint 1: Hint 2:
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Japanese Fusion Alphabet Soup

The Dish... ...is an intriguing blend, with a base of classic Western flavours, and a twist of the Orient at its heart. The Ingredients... ...are diverse and are combined in such an unexpected - ...
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I am an island (ysaujdiolkiun)

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids I received an envelope containing two drawings and no return address. I would recognize that handwriting anywhere - my dear friend ...
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Circuit Diagram

An entry to Fortnightly Topic Challenge #35: Restricted Title 1 - based on the following xkcd. Circuit diagrams can be quite difficult to understand, so here are some documents that will hopefully ...
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Five Slitherlinks

Solve five Slitherlinks, each with a unique solution. Please say a word regarding (or show an image depicting) each solution method.
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GRID-THIRTY-SIX

Solve 36 puzzles (or more) to find the final 6 letter answer.
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Introducing: Number Slope™

Number Slope™1 is an original2 grid deduction puzzle similar to Sudoku. It is solved on an n-by-n grid, tiled with n n-ominoes. The rules are: Each number from 1 to n must occur once and only once in ...
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Sudoku embedded in a Kakuro

In addition to standard Kakuro rules, the grey shaded cells must form a valid Sudoku solution. One sum in this puzzle has been corrected from 28 to 23. Fortunately, it was in a location that nobody ...
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One 'double agent' two-step on a waltzing floor

I'm in a jam – cornered I am! – No clue 'bout where to go Here's what went down, a pretty gown Some wine, a French chateau She whispered underneath her breath "Come dance with me and ...
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The Determinant Sudoku

The determinants of $2\times 2$ matrices are calculated this way: $$\det\begin{bmatrix}a & b \\c & d \end{bmatrix}=ad-bc$$ And here's the sudoku-determinant puzzle: What's the solution for ...
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fill this grid with water!

In this puzzle you should fill the imaginary small squares in each row and column up to the number that is written next to it with water. You can't fill a square if the squares connected to it(under ...
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I've been everywhere, man

I am a knight facing a plight My dearest one of all Lives in a tower and won’t come out Unless her name I call I went to pick her up today And though my mind was set To do so, as I ...
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WITLESS - A Puzzling Journey

IMPORTANT! READ ME: The only 'puzzle' parts of this are the links, titled 'Set X', 'Inscription X', or 'Constellation X'. Everything else is flavortext, apart from this readme section, although the ...
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Question 16 Ripple Effect

This is a Ripple Effect puzzle. The rules of this puzzle are: Fill in each region with numbers from 1 to n, where n is the region size. For instance, the top left region must have the numbers 1 to 5 ...
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A Six-Faced Puzzle

Here is a grid-deduction puzzle, whose mechanics I have seen under several names such as 'Castle Wall', which is the one I'll use here. The goal of Castle Wall is to draw a loop enclosing all the ...
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Parallelisation

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids Puzzlers, I am presenting a set of six duo-grids! Of course, I need to tell you how they work - you are given a grid. Looking at it,...
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Messages hidden in the “visit every square once” puzzle

I proposed my girlfriend yesterday, asking her to be my wife. but she did not answer me. Besides she gave me this 6 puzzles, below. She said I will know her answer after solving the puzzles. Inside ...
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Pikurossword, or: Three-in-One

This is an entry into the Fortnightly Topic Challenge #36. [edit: i hope this wasn't too bad for my first puzzle here! let me know how i did :)] The answer to this puzzle should answer the question: ...
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Making Things Difficult

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Factoring the Time Think fast! If you're looking for meaning, these clocks have some for you. Keyboards are Disgusting Gunky ...
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Coloring a 4 by 4 grid

I made this simple puzzle a couple of years ago. There are three colors which appear in every row and every column. Moreover, every color appears 5 or 6 times in total. Find the color of the square ...
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Oh no, it's another safe!

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids Oh, did I feel proud after solving the last safe... until I was immediately dimension-doored (or something) into this room! Damn ...
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Every Fourth Wormhole

An entry in Fortnightly Topic Challenge #33: Surface Geometry Mazes
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You go wherever you go today

A conclusion to my entries in the Fortnightly Topic Challenge #32: Grid Deduction Hybrids. This metapuzzle incorporates the three previous puzzles in this series: Desert Irrigation Project I am an ...
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HAISU (Room Count): An original grid-logic challenge

HAISU is a portmanteau of three Japanese words - 'hairu', to enter, 'su', number, and 'hausu', an English borrow word meaning house, of course. Together, we get a meaning of 'enter number house', ...
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My Uncle's Music Box

Unfortunately, my favorite uncle just passed away. He's the one that taught me all about puzzling, and supposedly found Davey Jones' treasure in his youth. I miss him very much, however, I just ...
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Curiouser and Curiouser

CHAPTER ONE Alice was beginning to get very tired of sitting by her sister on the bank, and of having nothing to do: when she was overcome with the strangest sense of deja vu, and saw a 7x3 grid of ...
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Popularity Within a Target Audience

This is a metapuzzle with four component puzzles and a final meta. Creations of CSIRO The Australian research institute CSIRO is notable for producing inventions such as gene shears, the insect ...
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Stingray Nebula

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Inspired by the title of this xkcd comic, but in no way related or affiliated beyond the shared name. This is the stingray nebula: ...
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Slightly Odd Sudoku

Someone I find very trustworthy continues to insist that this is a valid Sudoku board. It's been a while since I've played, but surely there's a couple of things off here, right? Alright, so that ...
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Untitled, for Now

As you step into the gallery, you notice an interesting piece of art hanging on the wall. "I like the piece, but what's with the title?" you ask the docent. "I'm used to obscure titles in modern art, ...
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Snakes on a Plane! 2

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Inspired by the title of this xkcd comic. Snakes ... on a plane ... again ... This time 2 specimens of a huge unknown type of snakes ...
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Help! Can you get my puzzle back?

Puzzling has a lot of really complicated stuff these days, so I just wanted to post a simple Boggle grid. You know that game, right? You form words by starting from one letter, then taking adjacent ...
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Introducing Domidoku!

Come one, come all! Come see the new type of logic puzzle, the Domidoku! Here's a sample for all to try! The process is simple! First you solve the Sudoku and then you solve the Dominosa! ...
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Shortest way from B to A

Spent most of my life out at sea I've crossed a shark or two – or three Stayed calm – a skipper brave and tough Yet one of them did call my bluff Gorged on my leg with glee Not yet ...
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Chess Connect Puzzle

I made up a new logic puzzle based on the games Numberlink and Chess, and thought it ended up rather interesting. The solution, as usual, is unique. The starting and ending positions of 7 chess ...
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Make numbers 0 - 11 using the digits 2, 0, 1, 8; BUT

... seriously, this is definitely NOT that "kind of puzzle"! ;) So let me create this puzzle to freshen you up! It is inspired by a meta question: Yet another 2018 puzzle. Put the digits 2, 0, 1, ...
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Introducing: Jormungand

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids Introducing: Jormungand A combination of Ouroboros (Slitherlink) and Numbersnake (Numbrix) to create the greatest snake-themed ...
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Three for the price of one

While browsing through your local puzzle store, you see something you can't resist: a box which promises two grid deduction puzzles for the price of one! The vendor explains that the box contains a ...
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Statue View: Tetrominoes

This is a Statue View puzzle, an original invention combining two logic puzzle genres: Statue Park and Canal View. Rules of Statue View: Shade some cells of the grid to form the given set of pieces. ...
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A Knight's Kuromasu

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids You are a knight in the king's army, and you've been tasked with constructing some walls. The problem is, as a knight, you are ...
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Hexagonal Grid Filling

Fill in each blank white hexagon with a digit from 1 to 9. Each of the grey hexagons is the sum of the white hexagons around it, and all of the white hexagons that are around the same grey hexagon ...
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Who can spot the difference?

My family and I have just moved house! Lucky us! So what did my family do? We held a housewarming party, and rung everyone in the neighbourhood up to invite them. So, anyway, people were coming in ...
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Sudoku with only 8 predefined numbers

Have fun with my self-made Sudoku puzzle. Solve this Sudoku puzzle using the standard Sudoku rules: Fill any row, column and bold-framed area with the numbers 1 to 9. Hint: It is not as difficult as ...