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.

Puzzles where the final state of a grid must be deduced logically through clues placed within and/or around the grid. Common puzzles of this type include Slitherlink, Sudoku (and Sudoku variants), Kakuro, Nurikabe, and Masyu.

As a general rule, a question with this tag should provide the rules of the given puzzle (unless e.g. deducing the rules is part of the puzzle). Don't assume everyone knows how, say, a Nurikabe works! Answers should explain the logical solve path. The site requests that you upload your deductions along with the solution (and not just edited in after) so others can follow the solution and see how the answer was achieved.

Not to be confused with in which a set of clues about correspondences between different ways of describing the same set of objects can be used to compose and fill a grid to solve them.

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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 flavortext does tell you that the meaning of the…
TheGreatEscaper
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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', which I have roughly translated to English as 'Room…
TheGreatEscaper
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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: Spectacular, isn't it? This is a nebula map of…
Alconja
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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 swallowed a part of the passengers on a plane.…
Sleafar
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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 following constraints: The arrangement is…
Tim C
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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 grid-logic puzzle the world has ever seen![Citation…
Sconibulus
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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 must be distinct. The answer's already available,…
Jason Kim
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HAISU: One Piece

This is a Haisu puzzle. Draw a path from S to G passing through all cells exactly once by connecting the centres of adjacent cells, such that when the path passes over a number N, it is on its Nth entry to the region which contains it. Enjoy! There…
boboquack
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Nurikabe: Hindsight in 2020

This is a Nurikabe puzzle. The goal is to shade some cells so that the resulting grid satisfies the following rules.1 Numbered cells are unshaded. Unshaded cells are divided into regions, all of which contain exactly one number. The number…
Jafe
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Partiti : solve this new type of puzzle

These are puzzles similar to Kakuro, which is the creation of a friend of mine whom I met last year: Rules: Place one or more digits from 1 to 9 in arbitrary order in each empty cell, such that a number in the top left corner of each cell is the…
ABcDexter
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Heteromino: Introduction

Heteromino is an area-dividing puzzle with very simple rules. I encountered this puzzle type on puzz.link, and seeing there's none posted here, I decided to give it a try. Here is an example puzzle with solution: The rules of Heteromino are as…
Bubbler
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Domatic lights - 4 colors

You must add red, green, blue and yellow light bulbs to the grid to satisfy these rules. Each white hex must contain either a red, green, blue or yellow light bulb. Light bulbs of the same color cannot be in neighboring hexes. Each white hex must…
Joshua Taylor
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Intersection Puzzle

I have invented a new puzzle called Intersection. Let's find out what it is! Intersection You are given an $n\times n$ grid with circles and boxes inside arbitrary squares. A circle cannot be in the same grid square as another box; there must…
Mr Pie
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Jewel Cave - A Statue Park-Cave Hybrid

The goal of this puzzle, a hybrid of Statue Park and Cave, is to place the given shapes into the grid, subject to the following rules. As in both original puzzles, all unshaded squares must form a single orthogonally (on a side) connected region. As…
Jeremy Dover
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Nurikabe: Roaring twenties

This is a Nurikabe puzzle. The goal is to paint some cells black so that the resulting grid satisfies the following rules.1 Numbered cells are white. White cells are divided into regions, all of which contain exactly one number. The number…
Jafe
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