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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1
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1answer
33 views

What's the next logical step for this Kakuro?

The puzzle is small but frustrating. Here's what I've deduced so far: In the 36 row, there are two missing digits which sum to 9, these must be 1+8 so the remaining empty cells are 2,3,4 In the 36 ...
6
votes
1answer
191 views

Existence of index-uniform Hashi puzzles

On the left, we have a starting configuration for a game of Hashi, and on the right, its solution: That is to say, the goal is to make connections (planar, and traveling only in cardinal directions) ...
13
votes
2answers
564 views

Encrypted Pentopia

Rules of Pentopia: Place some pentominoes into the grid (not necessarily all of them) so that they do not touch each other, not even diagonally. Pentominoes cannot repeat in the grid; rotations and ...
3
votes
0answers
124 views

Mega-puzzle of many number puzzles: Nikoli Octathlon

This puzzle has been my Moby Dick of puzzles for so long. It's from MellowMelon's old puzzle site and is a Nikoli-based megapuzzle with eight sub-puzzles. I'm copying the puzzle image from there so as ...
25
votes
2answers
1k views

Encrypted Snake (Grid Puzzle)

Rules of Snake: Shade some cells to form a non-intersecting path which does not touch itself, not even diagonally. Black circles must lie on one end of the path. White circles must lie somewhere ...
15
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1answer
347 views

Sum-until-1 Fillomino: Odds, Fibonacci, and Pi

Fillomino rules (taken from Nikoli): Fill in all empty cells with numbers under the following rules. Divide all of the board into blocks. Fill each block with the same number horizontally or ...
13
votes
1answer
264 views

Sub Battle Sudoku

Please find below a variant Sudoku which incorporates elements of Star Battle. The Sudoku is a standard irregular Sudoku, and the clues outside the grid are sandwich clues: the sum of digits strictly ...
8
votes
1answer
431 views

Where's the path?

A person was shading several unit squares in a square grid, to create a path from the bottom left corner to the top right corner. The path stepped from each square to the next either horizontally or ...
13
votes
1answer
261 views

Mid-loop: Coming Soon

Rules of Mid-loop: Draw a single loop passing through all of the black dots. The loop may not branch off, intersect, or move diagonally. The loop cannot bend at the black dot. Each black dots denotes ...
10
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2answers
315 views

Trio Tapa: Introduction

Rules of Tapa (copied from here): 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 clues in them. ...
14
votes
3answers
309 views

Cross ALL the Streams

This grid deduction puzzle is a hybrid of three puzzle types: Cross the Streams, Tapa and Star Battle; rules for each are summarized below. In this grid, every cell is to be shaded either red, blue, ...
17
votes
2answers
656 views

XV Sawtooth Sudoku

Please find below a variant Sudoku puzzle, based on a combinatorics problem I was having a look at. The timing is right, as I recently saw @BeastlyGerbil back in chat, and I know that user is a big ...
3
votes
1answer
587 views

A tough Word-Nurikabe puzzle

I came up with this Word Nurikabe Puzzle, which was NOT a part of the Puzzle Ramayan, the qualifiers for Indian Puzzle Championship. Rules Place the given words in the grids ‘islands’, so ...
2
votes
2answers
203 views

How to get started on this Slitherlink (No Swiss)?

This is a puzzle from Round 4 of WPF's Puzzle Grand Prix this year. It's a Slitherlink with the additional rule that "Every Swiss cross-shaped arrangement of five cells must contain at least one ...
-10
votes
0answers
123 views

MATHEMETICS GRADE 5 QUESTION DIFFICULTY LEVEL TOUGH

In a 3x3 grid, I'd have to put numbers from 1 to 9 in a manner so that respective row, column and diagonal add up to 14
7
votes
1answer
229 views

Toroidal Weaved Truncated Square Tiling Tapa

Rules of Toroidal Weaved Truncated Square Tiling Tapa: The grid wraps around horizontally and vertically and also is divided into several 1-cell and 3-cells tiles. Shade some tiles such that all ...
1
vote
1answer
241 views

Can Arrows puzzles have multiple solutions?

I am trying to make an Arrows puzzle, but I don't know if there are multiple solutions. For those who don't know, an Arrows puzzle starts with a grid of numbers (example from SE) surrounded by empty ...
3
votes
1answer
679 views

What's the next step for this Kakuro puzzle?

What's the next step for the below Kakuro puzzle? Source: Puzzle Page app
10
votes
1answer
174 views

3D Tapa - Count to Five

Rules of 3D Tapa: The grid is a 3-dimensional cubes, represented here by layers of cubes from top to bottom. Shade some cubes such that all shaded cubes form a single orthogonally (in 3-axis) ...
5
votes
1answer
468 views

The next steps for this Kakuro puzzle

What are the next steps for this Kakuro? I've solved most of it, but there is an area I'm stuck on. Source: Puzzle Page app
7
votes
1answer
307 views

“Puzzle Waffle”

A black man, tilting his head in satisfaction and checking it was about lunchtime, entered the Sphinx Café in downtown Washington D.C. on a Friday out of boredom with his usual lunch haunt and greeted ...
8
votes
2answers
462 views

A Sudoku With A Trick

Normal Sudoku rules apply in this puzzle. This is an incredibly difficult puzzle to solve and has a very clever and ingenious trick in it. I request solvers to show their work at different stages of ...
14
votes
1answer
719 views

Up like a rocket ship

This is a Palisade (or 6 Cells) puzzle. The rules are: Thicken some of the pentagons' sides so the thick borders outline regions of six pentagons apiece. Any pentagon with a number in it indicates ...
16
votes
1answer
350 views

A Dotless Kropki

Rules of Kropki: Each row and column contains one occurrence of each digit from one to the size of the grid. All pairs of orthogonally adjacent cells containing numbers with a 1:2 ratio are marked ...
3
votes
5answers
822 views

Can you fill the cells by integers? [duplicate]

Can you fill the cells with integers so that all the equalities must be true?
11
votes
1answer
249 views

Stostone - Aoi's Big Birthday

Rules of Stostone: Shade exactly one stone, an orthogonally-connected group of cells, in each region. No two stones in different regions are adjacent. If a number is in a region, it tells the size of ...
3
votes
1answer
196 views

Quadruped Mosaic

This is a visual puzzle (known as "mosaic" or "fill-a-pix") with the same rules as MineSweeper: This puzzle has exactly 100 x 100 cells. The grid is to be filled with colored and ...
5
votes
1answer
239 views

A brain[expletive] sudoku

This is a Sudoku that is also a Brainfuck program. The standard rules of Sudoku apply. The same symbol can not appear twice in the same row, column, or 3x3 box. The grid should also form a functioning ...
18
votes
1answer
564 views

Slitherknot (Double Slitherlink)

This is a variation on the classic Slitherlink Puzzle. However, instead of creating one loop, you must create 2 separate loops. The two loops can not share any edges, however they can cross or meet on ...
8
votes
1answer
223 views

Gaps - Square Numbers

Rules of Gaps: Fill some cells with stars, so that each row and column contains exactly two stars. The stars cannot touch each other, not even diagonally. Numbers outside the grid indicate the number ...
13
votes
1answer
887 views

A walk after dark

This is a Palisade (or n-Cells) puzzle. The rules are: Thicken some of the squares' sides so the thick borders outline cells. One such cell comprises just one square; one cell comprises precisely two ...
8
votes
3answers
323 views

Toroidal Pipes Puzzle: T's and Bulbs Only

A continuation in the Pipes puzzle series. Problem statement for math nerds: Let $G(N)$ denote the graph consisting of cardinally adjacently linked lattice points on an $N \times N$ toroidal grid. For ...
15
votes
1answer
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 ...
13
votes
1answer
455 views

Windmill: A Masyu Puzzle

The standard Masyu rules apply.
0
votes
1answer
96 views

How to solve the attached sudoku?

Please explain the logic. I am not trying to solve it using trial and error or using any software. I am just looking for the next step. This sudoku is from apple 'Sudoku King' app.
2
votes
1answer
168 views

How could I solve the attached Sudoku?

Please explain the logic. I am not trying to solve it using trial and error or using any software. I am just looking for the next step. This sudoku is from apple 'Sudoku King' app.
12
votes
1answer
292 views

9x9 Sudoku Slitherlink Hybrid

I previously created a combined slitherlink and sukoku puzzle, but I was unsatisfied because the grid was smaller then a regular sudoku. So I made another, larger one. Below is a 9 by 9 grid. This is ...
9
votes
1answer
163 views

Sudoku: Episode 64 - Attack of the Clones

An 8x8 Sudoku where you technically only have to figure out 32 cells! Twice Half the cells, double the clues! Penpa Link Rules Normal Sudoku rules apply. Values are 1-8. Boxes are the 4x2 regions ...
17
votes
2answers
612 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 ...
7
votes
1answer
216 views

A 3x3 grid with common factors

A $3 \times 3$ grid $G$ is filled with every number from the set $\{2,3,5,6,7,11,14,15,30\}$. Now a new $3 \times 3$ grid $H$ is formed, such that $H_{ij}$ is the number of neighbors of $G_{ij}$ that ...
11
votes
4answers
947 views

Deriving a 3x3 grid from another one

A $3 \times 3$ grid $G$ is filled with every number from $1$ to $9$. Now a new $3 \times 3$ grid $H$ is formed, such that $H_{ij}$ is the number of neighbors of $G_{ij}$ that are greater than $G_{ij}$....
5
votes
1answer
154 views

Sudoku + Slitherlink

I like combinations of puzzles, so I decided to combine a Sudoku and a Slitherlink. Below is a 6 by 6 grid. This is filled in with numbers based on the usual rules of sudoku. All of the numbers from 1 ...
-1
votes
1answer
125 views

Fillomino: Number Attack!

This is my first time making a Fillomino. Hope you enjoy! Fillomino (taken from Nikoli): Fill in all empty cells with numbers under the following rules. Divide all of the board into blocks. Fill ...
6
votes
1answer
112 views

A Somewhat Foolish Poem

Your task is to solve the Sudoku and complete the missing words in the following poem. Classic Sudoku: Each row column and box contains the digits 1-9. XV-rules: Digits separated by V must add to 5. ...
22
votes
1answer
561 views

Slitherlink: Around the W0rld

Rules of Slitherlink: Connect adjacent dots with vertical or horizontal lines to make a single loop. The numbers indicate how many lines surround it, while empty cells may be surrounded by any number ...
-1
votes
1answer
135 views

Skyscrapers 7x7 How to get next Skyscraper on field

I have the following Skyscrapers puzzle: C3 C1 C2 C3 C4 C4 C2 C2 V3 C5 C4 V1 C1 C3 C4 C2 V5 C3 C3 V7 C3 C3 V4 V2 C2 C1 V2 C2 C1 C3 C4 C2 C2 C2 C2 C -> Clues how many ...
23
votes
1answer
760 views

Polly O'Mino's Hexcellent Adventure

An entry in Fortnightly Topic Challenge #52: Polyominoes. I had heard that my good friend Ingrid Deduction was back in town, so I popped round to her apartment today, only to find she'd got herself a ...
10
votes
3answers
915 views

Calculation Sudoku

Here is a new quiz from my daily quiz calendar. I'm trying to find a way to solve it. The numbers 1-6 should be filled in. And like a sudoku, each row and each column should contain each number ...
18
votes
1answer
403 views

A constrained, but concerning, celestial confrontation

An entry in Fortnightly Topic Challenge #52: Polyominoes. This puzzle is a hybrid between Pentominous and Star Battle. Your job is to divide the grid below into pentominoes according to the rules of ...
1
vote
1answer
120 views

Next Move on this Sudoku Classic

What would be the next move? Link to this sudoku

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2 3 4 5
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