# 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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### 3D nonogram, beginner's edition

Trying out the concept of 3D nonograms. This one should be pretty simple. Name the depicted object.
1k views

### Sudoku in the third dimension (3D Sudoku)

People seemed to enjoy my last Sudoku variant puzzle - Samurai Pseudoku, so I spent this week making another! This one is going to require using logic you've never used before... The last one was a ...
1k views

### Tic tac toe - Sudoku: A variation in which the centre box defines the layout of the other boxes

I stumbled across this interesting variation of Sudoku the other day and thought I'd give it a try, it has however baffled me and I've been unable to progress past the very early stages. The puzzle ...
1k views

### When you stop at the top of a Ferris wheel

This is a Palisade (or Ten-Cells) puzzle. The rules are: Thicken some of the squares' sides so the thick borders outline cells of ten squares apiece. Any square with a number in it indicates how many ...
510 views

### Mosaic by Albrecht Dürer

This is a visual puzzle (known as "mosaic" or "fill-a-pix") with the same rules as MineSweeper: The grid is to be filled with colored and white tessera. Choose whatever color you like for the colored ...
1k views

### A “Letter” Slope puzzle?

Your brother has been forcing you to some read some of his frankly ridiculous poetry, so, knowing that he was never a numbers man, you decide to vex him with a Number Slope puzzle. In fact, you are so ...
2k views

### 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,...
1k views

### 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 ...
801 views

### Hokuro Puzzle: Introduction

This is an entry for Fortnightly Topic Challenge #44: Introduce a new grid deduction genre to the community. This puzzle type is inspired by Kakuro, and it has similar rules. Kakuro is short for '...
648 views

### 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 ...
1k views

### 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 ...
2k views

### 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 ...
610 views

### Pipes Puzzle Uniqueness

In the puzzle game Pipes, a space-filling tree of pipes (which may have either one, two, or three neighboring connections each, but not four) is scrambled by a series of tile rotations, and the goal ...
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### A problem about Yin-Yang puzzles

In a Yin-Yang puzzle, one must fill every cell with either a black circle or a white circle according to the following rules: All cells with black circles form an edge-connected region. All cells ...
550 views

### Kropki Sudoku – Sudoku based on the relation between neighbouring numbers

This puzzle is named Kropki Sudoku. The classic sudoku rules apply: Place numbers on the grid below such that each row, column and 3×3 box contain the numbers 1 to 9. A white dot indicates that the ...
2k views

### Sudoku variation: Using various chess moves, solve the grid from just two numbers

I've been watching a youtube channel hosted by puzzlers and attempting the sudoku variation they post each day. Today's I found particularly interesting and while sharing it around it proved quite the ...
659 views

### Slitherlink - It's all in the 2s

Can you solve this Slitherlink puzzle that I came up with? And in CSV: 3 - 3 - 2 - - 2 - 2 - 2 - - 1 1 2 2 1 - - 2 - 2 2 - - - 2 - 1 2 - - 1 - I tried to ...
507 views

### 3D nonogram – What's in the box?

This is a three-dimensional nonogram. The first six squares depict the layers of a $6\times6\times6$ cube. The final square gives the enumerations for the Z-axis, top to bottom. Some rules: The grid ...
710 views

### 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 ...
457 views

### Humans, vampires and mirrors

Here is a room composed of $10 \times 10$ squared cells. Some cells contain a double-faced mirror ( / or \ ) that reflects the light with an angle of $90°$ on both sides. The other cells can be empty (...
620 views

### Oriental House: An original grid-deduction challenge

A different approach to an old concept of mine, Oriental House is a new grid-deduction puzzle based once again off exits and entries. The rules are as follows: Draw a path from S to F, passing ...
1k views

### JonMark Perry's Grid Logic Puzzle

Consider the following puzzle type proposed by JonMark Perry. Start with a square grid of arrows, each one pointing in one of the four cardinal directions. For example: You start at the top left. ...
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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 ...
972 views

### Complaint at the PSE lounge

While walking through the PSE lounge, I noticed a piece of paper on one of the tables. Picking it up, I saw several things. The first, was a couple of sentences at the top: I love this place! But ...
637 views

### Chain Puzzle: Tabletop Games #05 - It's Yahtzee, Jim, but not as we know it

This is the fifth Chain Puzzle in the Tabletop Games series, in which all puzzles are themed around board games, card games, tile games, and the like. The answer to this puzzle is a thematic word or ...
605 views

### Heyawacky: Ace of Cups

This is a Heyawacky puzzle. The rules are the same as Heyawake, but non-rectangular regions are allowed. Rules of Heyawake: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent;...
845 views

### HAISU: Nought and Crosses

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', ...
2k views

### An Ailing Assassin

Since moving to the countryside, I've taken up a side job as an assassin. While camping out with a doctor, they told me that I had contracted an illness. However, since I didn't take any money with me,...
534 views

Rules: Hey, this looks like slitherlink! In fact, it is two slitherlinks added together. So both of the two slitherlinks have clues in exactly the same locations as this grid below. Furthermore, a 2 ...
765 views

### Slitherlink Fillomino hybrid

This puzzle is a combination between a Slitherlink and a Fillomino. You should put a number in each square and draw a single closed loop over the grid such that the following properties are satisfied:...
625 views

### Pentominous - P is for…

This is a Pentominous puzzle. Rules of Pentominous: Dissect the grid into regions of 5 cells each. No two regions of the same shape can be adjacent (but they may touch at a corner). Rotations and ...
497 views

### Trichain: A Bottle of Rum

This is a Trichain puzzle. The rules of Trichain are as follows: Numbers must be white, and match the size of their white islands. Each white island can only contain at most one number. Some white ...
369 views

### Statue View: Raindrops

This is a Statue View puzzle, an original invention combining two logic puzzle genres: Statue Park and Canal View. It is harder than my previous Statue View, so you may want to start there. Rules of ...
663 views

### Tetromino minesweeper: the Amphitheater

This is a minesweeper puzzle with a tetromino twist. The goal is to place mines in the grid, following a few constraints. Rules: A number indicates how many adjacent (including diagonally adjacent) ...
521 views

### On The Subject of X-Rays

(This is part of a series of puzzles written for Timwi for a Secret Santa puzzle exchange, themed around various custom modules for the game Keep Talking and Nobody Explodes. No KTaNE knowledge is ...
369 views

### Greener Grasses: Around the Trees

This is an entry for Fortnightly Topic Challenge #44: Introduce a new grid deduction genre to the community. Greener Grasses is apparently a new genre of grid puzzle. Pitched by Joseph Howard and ...
870 views

### The Peculiar File

So I was browsing through my computer files earlier and I found a file I'd not seen before. I was wondering if you guys could help me figure out what it's about. This is where I found it: This is ...
457 views

### Santoitchi: Introduction

Santoitchi is yet another genre involving trominoes. It appears to be invented by Inaba Naoki, and then picked up by Bram de Laat, who uses the name Sandwich (blame Google Translate for the possible ...
435 views

### Double feature: Legal trouble

This puzzle is part 6 of the Double feature series (first part here). The series will continue in "Double feature: Weightier". Rules of Hitori1 Shade some cells in the grid. No ...
401 views

### Double feature: Bibliophile edition

This puzzle is part 12 of the Double feature series (first part here). The series will conclude in "Double features: The wrap-up". Rules of Tents and Trees1 Place a number of tents ...
412 views

### 1, 2, 3… Trinary!!! (SS#2)

An entry in Fortnightly Topic Challenge #47: "Wacky Sudokus" Other puzzles in this series Welcome to the second puzzle in this suduko series! For more information about the series, see the ...
1k views

### What is a “unique solution” in a Slitherlink puzzle?

In the question Five Slitherlinks, the querent suggests that "each [Slitherlink puzzle has] a complete solution". I'm newly reading about Slitherlinks, but I don't understand what makes a solution "...
510 views

### Double feature: In cold blood

This puzzle is part 5 of the Double feature series (first part here). The series will continue in "Double feature: Legal trouble". Rules of Nurikabe1 Shade some cells in the grid. ...
761 views

### Haisu: Pixel Perfect

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', ...
961 views

### A spartan skeleton Sudoku

A skeleton crossword is a crossword where the black and white squares aren't given; you have to deduce them. Here's a generalisation of that idea to the Sudoku puzzle. Here's a 4 by 4 grid, with four ...
378 views

### Have you heard Gokigen Naname?

Here is a regular Gokigen Naname a.k.a Slalom a.k.a Slant puzzle. An online (mobile-friendly) version is available here. Rules: Put a slash (diagonal line) on each cell. Each number ...
1k views

### Is there another name for this puzzle? (Kyudoku, Nine Find)

Is there another name for this type of puzzle? I can only find two examples of it online: https://www.brainzilla.com/logic/kyudoku/ http://ninefind.com/ In the game you start with a 6x6 grid filled ...
317 views

### 3D tetromino placement

The following image depicts a $5\times5\times5$ cube. Insert any number of the pictured 3D-tetromino pieces into the cube to satisfy the conditions listed below. Pieces may be rotated in any direction....