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.
349 questions
25
votes
2
answers
2k
views
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 ...
- 81.1k
14
votes
1
answer
919
views
The Blind Killer - a new series! SS#1
An entry in Fortnightly Topic Challenge #47: "Wacky Sudokus"
Other puzzles in this series
Welcome to a new sudoku series! This series will run for the duration of the current Fortnightly ...
- 64.9k
16
votes
2
answers
1k
views
Twelve Labours - #02 Lernaean Hydration
This puzzle is part of the ‘Twelve Labours’ series. Previous instalments can be found here: Prologue | 01
His first labour now complete, Hercules made his way up the street to the storage depot for ...
- 155k
12
votes
1
answer
796
views
Double feature: Braaains
This puzzle is part 1 of the Double feature series. The series will continue in "Double feature: Russian desman".
Rules of Akari (also known as Light Up)1
Insert light bulbs into any ...
- 81.1k
15
votes
1
answer
1k
views
Heyacrazy: Crosses
This is a Heyacrazy puzzle.
Heyacrazy is an original genre, inspired by the "two border" rule of Heyawake and Heyawacky.
Rules of Heyacrazy:
Shade some cells of the grid.
Shaded cells ...
- 151k
14
votes
2
answers
1k
views
(1 of 11: Numberlink) What is Pyramid Cult's Favorite Activity?
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 ...
- 34.4k
23
votes
1
answer
1k
views
Statue Park: Knight's Lines
This is a Statue Park puzzle.
Rules of Statue Park:
Shade some cells of the grid to form the given set of pieces. Pieces may be rotated or reflected.
Pieces cannot be orthogonally adjacent (though ...
- 151k
17
votes
1
answer
911
views
Tapa - Confluence
This is a Tapa puzzle.
Rules of Tapa:
Shade some cells of the grid. Shaded cells should form a single [orthogonally] connected group; no 2×2 square should be fully shaded.
Some cells have ...
- 151k
12
votes
1
answer
374
views
Follow the path of relation through the grid #1
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
107
votes
2
answers
8k
views
This new puzzle type needs a name
I believe I have invented a new type of puzzle...
What is its name?
Colour-blind-friendly version available here.
Begin by solving the 16x16 sudoku; each of the digits 1-16 must appear exactly ...
- 155k
16
votes
3
answers
2k
views
How does one go about creating a new grid-deduction puzzle?
The grid-deduction tag covers puzzles like Sudoku, Kakuro, etc. where the goal is to fill in a grid of numbers [/letters/colours] in a unique way by logical deduction from some predetermined rules and ...
- 118k
8
votes
1
answer
644
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 ...
- 34.4k
7
votes
1
answer
282
views
Follow the path of relation through the grid #2
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
6
votes
1
answer
230
views
Follow the path of relation through the grid #3
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
13
votes
1
answer
594
views
Twelve Labours - #07 Cleats 'N' Balls
This puzzle is part of the ‘Twelve Labours’ series, but can be solved independently. Previous instalments can be found here: Prologue | 01 | 02 | 03 | 04 | 05 | 06
Emerging from the barbers with a ...
- 155k
60
votes
4
answers
85k
views
What is the maximum number of solutions a Sudoku puzzle can have?
I've seen Sudoku puzzles that can be solved two different ways. Referring to a traditional 9x9 grid:
Is it possible for a Sudoku puzzle to have more than two solutions? If so, what is the maximum ...
- 2,533
26
votes
4
answers
2k
views
Another new puzzle type needs a name
For an example of how this type of puzzle works, see here...
I believe I have invented another new type of puzzle...
What is its name?
Colour-blind-friendly version available here.
Begin by ...
- 155k
23
votes
2
answers
704
views
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. ...
- 151k
14
votes
1
answer
612
views
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 ...
- 81.1k
14
votes
1
answer
2k
views
Strategy for solving 0hh1 and Unruly?
Q42's game 0hh1 and Simon Tatham's game Unruly are two almost identical logical deduction games. In each one, we're given a square grid which is to be filled by tiles of two colours, and a certain ...
- 118k
6
votes
1
answer
298
views
Piece de Resistance - Eight Doubled Tetrominoes Make a Tetronogram
Eight Doubled Tetrominoes Make a Tetronogram
This puzzle is part of the "Piece de Resistance" series. Go back to Part 1 (Ace) for the story.Ace Two Three Four Five Six Seven Eight ...
Time for ...
- 21.7k
3
votes
1
answer
172
views
Follow the path of relation through the grid #4
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
-2
votes
7
answers
19k
views
2x2 row and column equations
Rules: No paper or notes, but a calculator is accepted.
Post the exact time min wise of how long it took.
And obviously give the answer.
- 569
34
votes
2
answers
3k
views
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 ...
- 151k
29
votes
1
answer
2k
views
Captain Pun's new boat
My good friend Captain Pun has bought a new boat.
"And this is a picture of its sail!" he said, showing me this:
"Solve the nonogram and you'll soon know what type of boat it is!"
Can you solve ...
- 155k
20
votes
5
answers
1k
views
Square Spin #1: Sun and Moon
Defining Square Spin
Lets play a game!
The aim of this game is to transform one image into another using the least amount of moves possible. Here is what a move consists of:
...
- 2,905
19
votes
1
answer
676
views
Trichain: Introduction
Next: Trichain: Going Higher
Trichain is a new puzzle type I invented. It is somewhat similar to Nurikabe, but it uses a chain of L-trominoes instead of a continuous wall.
Example puzzle with ...
- 17.1k
16
votes
1
answer
724
views
Barrel - Part 1
An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Title based on the very first xkcd. Continued in Barrel - Part 2, Barrel - Part 3, Barrel - Part 4, and Barrel - Part 5.
You manage a ...
- 14.5k
13
votes
1
answer
457
views
Nurikabe: A Gentle Walk in the Hall of Giants
This puzzle is a Nurikabe that is designed to be a gentle introduction to the genre, with a learning curve of progressively harder deductions. It is encouraged for first-time solvers and those who ...
- 3,429
13
votes
1
answer
581
views
Cross the Streams: Three?
This is an entry for Fortnightly Topic Challenge #44: Introduce a new grid deduction genre to the community.
Here is a standard Cross the Streams puzzle. The genre is invented by Grant Fikes which ...
- 34.4k
10
votes
1
answer
718
views
Is ambiguity prevention sufficient reason to infer a clue?
I decided to work my way through Simon Tatham's puzzle collection to broaden my puzzling skills, and have reached the game Dominosa
I have a subboard below, where I've eliminated the possibility of 9/...
- 19.8k
5
votes
2
answers
239
views
Follow the path of relation through the grid #5
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
44
votes
4
answers
8k
views
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 ...
- 12k
28
votes
1
answer
2k
views
This new puzzle type needs a name {3}
I believe I have invented** a new type of puzzle...
What is its name?
** Well, 'adapted' an existing one, really...
Colour-blind-friendly version available here. Those without colour-blindness ...
- 155k
27
votes
2
answers
2k
views
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', ...
- 12k
25
votes
2
answers
2k
views
Introducing: Compoundoku!
Rules of Compoundoku:
Solve both left and right Sudokus.
In addition, the board below them is the Compound Board of both Sudokus.
Each number on the Compound Board should tell either: (1) ...
- 34.4k
18
votes
1
answer
758
views
A new nameless game
This is a new game I came up with the night after my birthday. It's so simple that I couldn't sleep just thinking about it. The rules are easy: you have to place all the two-digit combinations (...
- 2,155
17
votes
1
answer
843
views
Ingrid Deduction pops by with a puzzle
The other night I was sat at home in Providence when the doorbell rang. To my surprise, my very good friend Ingrid Deduction stood on the step, a huge grin on her face and a piece of paper held out ...
- 155k
15
votes
1
answer
781
views
PSE Advent Calendar 2021 (Day 13): A Christmas Hokuro
This puzzle is part of the Puzzling StackExchange Advent Calendar 2021. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door >
Hokuro is a ...
- 6,969
14
votes
2
answers
899
views
PSE Advent Calendar 2021 (Day 4): Decorating with Ingrid Deduction
This puzzle is part of the Puzzling StackExchange Advent Calendar 2021. The accepted answer to this question will be awarded a bounty worth 50 reputation. < Previous Door Next Door >
"...
- 29.2k
13
votes
3
answers
1k
views
What is the minimum amount of numbers needed to create a 4x4 Hidato with a unique solution?
Goal of Hidato:
Fill in a grid with a series of consecutive numbers that connect each other horizontally, vertically, or diagonally.
So I have been working on figuring out the minimum number of ...
- 2,809
11
votes
1
answer
748
views
PSE Advent Calendar 2021 (Day 19): Santa's Dilemma
This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2021. The accepted answer to this question will be awarded a bounty worth 100 reputation.< Previous Door Next Door >
It was ...
- 2,967
7
votes
2
answers
474
views
Square Spin #2: Climb the Mountain!
Square Spin History: #1>#2
New Rules
This puzzle introduces two new square types:
Unmovable squares (Un)
Replaceable squares (Re)
Plus the concept of ambiguity!
Ambiguity of squares
Certain ...
- 2,905
5
votes
1
answer
157
views
Follow the path of relation through the grid #6
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
5
votes
2
answers
252
views
Monday's Dominosa Problem
Dominosa or Domino Solitaire is a logic puzzle with a similar feel to Sudoku. Given a grid of numbers, you have to lay out the dominoes so they match the numbers, without duplicated or missing ...
- 2,737
-1
votes
1
answer
486
views
Sudoku variants #1: Schrödinger's Grave (6x6 grid)
Not in conjunction with my Minesweeper puzzles - that would be concerning!
Inspired by Cracking The Cryptic's video "The Graveyard Of Schrödinger" (original gimmick by fjam)
How this ...
- 2,809
85
votes
2
answers
5k
views
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 ...
- 4,639
68
votes
2
answers
5k
views
Sudoku like you've never seen it before
I've spent this week trying to create a difficult logic puzzle which is a combination of two Sudoku varaints, 'Samuari Sudokus' and 'Pseudokus', and this combo is unlike anything you can find online. ...
- 64.9k
57
votes
1
answer
3k
views
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 - dare ...
- 37.5k
52
votes
5
answers
5k
views
Prime Number Snake
Place numbers 1 to 100 in the cells of the 10 x 10 board below in such a way that consecutive numbers occupy neighboring cells (either horizontally or vertically). Shaded cells should contain only ...
- 19.2k