Episode #125 of the Stack Overflow podcast is here. We talk Tilde Club and mechanical keyboards. Listen now

# 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.

319 questions
Filter by
Sorted by
Tagged with
645 views

### A Family Reunion

Names have been changed to preserve anonymity A group of 25 people, A to Y, arrived at Z's door to celebrate the family reunion. They each had something to show off. Z: I know you're all excited ...
621 views

### Yajilin minicubes: the Hullabaloo, the Brouhaha, the Bangarang

These are three-dimensional yajilin puzzles. In each puzzle, the four squares depict the layers of a $4\times4\times4$ cube. Shade some cells on each layer. The numbered cells show how many ...
175 views

### Heyacrazy: “LMI”

This is a Heyacrazy puzzle, originally constructed for a test for Logic Masters India. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded ...
215 views

This is the evil older brother of this puzzle. I'm posting it more out of scientific curiosity than because it is a fun puzzle, because it is not a fun puzzle. It's just really hard. I wrote a ...
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 "...
576 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', ...
449 views

### Cryptic Crossword Sudoku

This puzzle is inspired by Matt’s excellent Cryptic Sucrosswordoku. Below is a sudoku as well as some cryptic clues. The clues lack enumeration and are in no particular order. The solutions to the ...
315 views

### Quick Tilepaint Puzzles: Corridors and Corners

Tilepaint (adapted from Nikoli) The areas enclosed by bold lines are called "Tiles" and color the tiles with the following rules. The cells of a tile must all be colored with black or left ...
303 views

### (6 of 11: Yajilin) What is Pyramid Cult's Favorite Places?

Dear PSE users and moderators, I’m new here in PSE, but I really need your help. There was this person who gave me a black envelope consisting 10+1 pages of puzzles, and also a scribble saying: “Find ...
986 views

### Logic 5x5 Letter Number Combination Grid

Hey I just thought other might enjoy the challenge of this puzzle as much as I did. Not the most easy thing to solve. Sort of like Sudoku, each row and column needs the letters A,B,C,D,E and each row ...
334 views

### Statue Park: Five

This is a Statue Park puzzle (originally constructed for the 2019 24-Hour Puzzle Championship, as part of a Tarot card themed set -- no prizes for guessing which rank this puzzle was). Rules of ...
327 views

### Double feature: Weightier

This puzzle is part 7 of the Double feature series (first part here). The series will continue in "Double feature: Going postal". Rules of Statue View1 Insert the four given pieces (<...
769 views

### How will you save Mike?

A direct hint: this question. Question starts from here: You are Dr. Nathaniel - a renowned archaeologist, and involved in a research about an ancient site. But, there is only one problem - the ...
251 views

### 4 pieces into a big slitherlink

Arrange the 4 pieces into a big slitherlink. To help you arrange it, First find the solvable small slitherlink then put it in the bottom-left position. 1st piece 2nd piece 3rd piece 4th piece
232 views

### Vertical and Horizontal Bars - An Instructionless Puzzle

Study the 2 examples given on the left and solve the puzzle on the right! The solution for each puzzle can be uniquely determined.
482 views

### Ripple effects: A suite of puzzles and conundrums

Best explained here. Basically there are two rules: fill in each region with the numbers 1 to N, where N is the size of that region two numbers, both K, cannot both be in the same row or column if ...
524 views

### Tetromi-nuri-doku

Note: This puzzle was inspired by the one here, by Mike Q. Every square in the grid above, when the puzzle is complete, has a number between 1 and 9 in it and either is shaded or is not. Each 3x3 ...
379 views

### Grandma's keynote

Found this note which is addressed To my grandma, in her chest Since she's passed now, here's my quest.. What tickled her interest? And who invited her as guest?
236 views

### Quick Ripple Effect Puzzle: $70$ Empty Cells

Ripple Effect (taken from Nikoli) The areas divided by bold lines are called "rooms". Fill in all empty cells with numbers under the following rules. Each room contains consecutive numbers ...
609 views

### Getting all same side pairs

The goal is to get same side pairs of the 6 tiles, , to fit into a $2\times 3$ grid, so that all touching sides match like so (excluding the red part), for example:
978 views

### 3D? No-no! 3 Sides

Introducing the Isometric Nonogram! α) "Boar"ing Definition [oink] Column: Blue Part + Green Cell Row: Yellow Part + Green Cell Adjacent/ Continuous cells: Purple Cell + any of the Orange ...
222 views

### You Sign Me Right Round

This is a 9x9 grid, with a sign in the center cell like shown. You can add signs to this grid one at a time following these rules: Each sign placed must point to the next sign placed Placed signs ...
302 views

### Backwards Boggle

I came up with a fun little 1-player puzzle for myself to do when bored. Pick 5-6 words, preferably words that share a good number of letters, and try to create a Boggle board containing all of those ...
748 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 ...
289 views

### Double feature: In concert

This puzzle is part 3 of the Double feature series (first part here). The series will continue in "Double feature: Hot stuff". Rules of Ripple Effect1 Fill the grid so that each cell ...
293 views

### Spiral Stumper Series: Instructionless Puzzle

Spiral Stumper Series is a $5$-puzzles series taken from the Final Round of a local (national) contest, KPK, which has been ended recently and authored by me. The theme is spiral and each puzzle is ...
381 views

### (5 of 11: Slitherlink) What is Pyramid Cult's Favorite Person?

Dear PSE users and moderators, I’m new here in PSE, but I really need your help. There was this person who gave me a black envelope consisting 10+1 pages of puzzles, and also a scribble saying: “Find ...
288 views

### Not Just Black and White

Answer for this puzzle is one word. Have fun! Highlighted parts are where I realised I have clued it wrong... Sorry for all this inconvenience! Hint: usefulness level 1 usefulness level 2 This ...
328 views

### Square Spin #4: Rude Awakening

Square Spin History: #1>#2>#3>#4 New Rule This puzzle introduces a new square type: Lonely squares (Ly) Lonely squares This type of square contains a box and it is ...
434 views

### A “Find the Path” Puzzle

I invented a puzzle, inspired by Simon Tatham's Portable Puzzle Collection. Is there anything that it could improve on? Was it too easy, or was it too hard? Anything I could add? What must I call it? ...
249 views

### Unusual Sudoku Puzzle

Find the solution to this Sudoku puzzle. The only problem is there aren't any normal Sudoku clues. Instead there are only some cryptic clues. What is the solution and how does the puzzle work? Edit: ...
535 views

### Ambiguous Grids

After six to eight weeks of waiting, your Shmikoli™ Ambiguous Grid Deduction Puzzle Set has finally arrived! You tear into the box only to discover that the instructions are missing. You shouldn't ...
343 views

### (10 of 11: Nurikabe) What is Pyramid Cult's Favorite Topic?

Dear PSE users and moderators, I’m new here in PSE, but I really need your help. There was this person who gave me a black envelope consisting 10+1 pages of puzzles, and also a scribble saying: “Find ...
253 views

### Grid puzzle solutions

I have a simple grid puzzle: Example: | X | Y | X | | Y | X | Y | | Y | X | Y | The move is defined as a row or a column move. So when you move one cell, ...
369 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. ...
147 views

### Nurikabe minicubes: the Headache, the Panache, the Apache

These are three-dimensional Nurikabe puzzles. In each case, the four squares represent the layers of a $4\times4\times4$ cube. The goal is to shade some cells in each layer so that the resulting space ...
298 views

### A Sincere Nurikabe Puzzle

So here's a standard Nurikabe puzzle. I'll be using the final (solved) grid for my upcoming local puzzle competition logo as it will spell the abbreviation of the competition name. So, what does it ...
441 views

### I'm Bad at Naming Things, so Just Try to Solve this Patterned Masyu Puzzle!

$\hskip1in$ The original Masyu rules apply. Make a single loop with lines passing through the centers of cells, horizontally or vertically. The loop never crosses itself, branches off, ...
278 views

### Puzzles: Meander

I have come up with an interesting type of puzzle based on the mathematical concept of a meander. The concept, of course, is not original to me, but the type of puzzle is, as far as I know. A ...
1k views

### Fill this 5x5 number grid incrementally, either by moving two boxes diagonally or moving three boxes in a row or column

One day, a friend has shown me a 5 by 5 grid, challenging me to fill it with numbers from 1 to 25. Obviously, it is not simple because there are some rules: The number 1 is placed in the center of ...
473 views

### Revenge of the Cryptic Crossword Sudoku

This puzzle is inspired by Matt’s excellent Cryptic Sucrosswordoku. Below is a sudoku as well as some cryptic clues. The clues lack enumeration and are in no relevant order. The solutions to the ...
279 views

### Mixed-breeds are puzzles too!

This is a three-dimensional mixed-breed puzzle. The five squares depict the five layers of a $5\times5\times5$ cube. The goal is to solve the odd-numbered layers as yajilin and even-numbered layers as ...
182 views

### Yajisan-Kazusan: Diagonal Arrows

This is a Yajisan-Kazusan puzzle. Rules of Yajisan-Kazusan: Several numbered arrows are given in the grid. Shade some cells so that: no two shaded cells are adjacent unshaded cells form ...
493 views

### The Knights and the Hounds

(With thanks and congratulations to Lee Leon) We rejoin our heroes several days after the events of The Knights' Gift, at the head of a pack of enormous staghounds, 1000 strong. Such a pack ...
742 views

### 13-by-13 SIKAKU puzzle

A SIKAKU puzzle consists of a square or rectangular grid in which some of the cells contain a one or two digit number. To complete the puzzle, a Solver must divide the puzzle into a number of ...
203 views

### Restoring 3D Tetromino Puzzle

You won't believe this. I worked all night to make a new 3D tetromino puzzle, and just as I was about to save the final version there was a power outage! Now I can't remember what the final clues were ...
754 views

### Algebra Sudoku: Dozens

Alas, the grid deduction fortnightly is over, but my love for the genre remains the same - i.e. very high. So, here is another grid deduction puzzle. An algebra sudoku! I think the rules are fairly ...
164 views

### Heyacrazy: Forks

This is a Heyacrazy puzzle. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally connected. When the puzzle is ...