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.

Filter by
Sorted by
Tagged with
14
votes
1answer
807 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
262 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 ...
0
votes
0answers
63 views

Sudokus with additional constraints [closed]

This sudoku has only 4 leads, but a lot of additional constraints. For starters Where can I find more Sudokus with additional constraints? What is the "maximum minimum" distance of two ...
16
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
411 views

Windmill: A Masyu Puzzle

The standard Masyu rules apply.
0
votes
1answer
62 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
142 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.
8
votes
0answers
157 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
129 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
548 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 ...
6
votes
1answer
196 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
919 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
120 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
113 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
92 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. ...
21
votes
1answer
518 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
122 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 ...
22
votes
1answer
719 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
881 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
372 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
105 views

Next Move on this Sudoku Classic

What would be the next move? Link to this sudoku
4
votes
3answers
781 views

Why is the next Sudoku step a 6?

I used a step-by-step Sudoku solver for a puzzle in which I was stuck. However I don't understand how the next number (6) was found. Sudoku puzzle where I was stuck: Sudoku puzzle solved by one step ...
1
vote
1answer
90 views

4-DominoBrane #002 “81”

Here is another domino puzzle. This is considerably easier than puzzle set earlier this week, and definitely doesn’t need bifurcation. This uses 4-Dominoes (all the normal dominoes, minus any with a 5 ...
13
votes
1answer
284 views

Tapa on a Penrose Tiling

An entry in Fortnightly Topic Challenge #51: Non-rectangular grids. This is a standard Tapa puzzle, on a non-standard Tapa grid...the "grid" is a Penrose tiling! Since the grid is not ...
3
votes
1answer
226 views

Slitherlink: The Couple of Question Marks

This is my first slitherlink puzzle. I made it myself. Feedback is appreciated! (I hope this one has a unique solution, unlike my other past puzzles, wink). Rules of Slitherlink (taken from Nikoli): ...
1
vote
1answer
122 views

4-DominoBrane Exclusive

Here is a smaller puzzle from the set of domino puzzles, I call DominoBrane. This uses 4-Dominoes (all the normal dominoes, minus any with a 5 or a 6). Each domino ...
4
votes
1answer
154 views

DominoBrane - Chained Domino Fitting

So I've been working on a set of domino puzzles, I call DominoBrane recently, it's sort of similar to Dominosa - except that, unlike Dominosa, the rules of the ...
15
votes
1answer
296 views

Haisu: Schezo's Birthday

Rules of Haisu: Draw a path from S to G passing through all white cells exactly once by connecting the centres of adjacent cells. When the path passes over a number N, it is on its N-th entry to the ...
10
votes
1answer
291 views

The Nurikabe of Peace

Today is the 75th anniversary of Sir Winston Churchill's speech "The Sinews of Peace" which introduced to the world the phrase "The Iron Curtain". This puzzle is inspired by that ...
8
votes
2answers
214 views

Double sudoku - two-digit numbers, the 1s and 10s places both form Sudokus [closed]

Using distinct 2-digit numbers from 11-99 that have no zeros, fill in the grid so that the tens digits form a Sudoku and the units digits form a (different) Sudoku. There might be a mathematical way ...
19
votes
1answer
407 views

Escape from Sudoku!

An entry in Fortnightly Topic Challenge #50: Escape Rooms I hesitated to enter this in the Escape Room FTC, but I definitely was inspired by the challenge to create this puzzle, and it is, in some ...
9
votes
0answers
361 views

The Puzzling Free-to-Play Escape Room, naturally!

An entry in Fortnightly Topic Challenge #50: Escape Rooms Without revealing too much, knowledge of geek culture and/or superb Google skills are required for this puzzle. Coming from an anime ...
1
vote
4answers
150 views

I need some help with this 15x15 nonogram

I have been working on this nonogram for some time and can't seen to figure out what to do next... This is the link: https://nonograms-katana.com/play/#game
8
votes
1answer
217 views

Nurikabe: The Terrible Tower of Threes!

This puzzle is a quick and fun little Nurikabe that is very tall, because I am not. It's not particularly tough, but if you need a nice relaxing grid-deduction puzzle to calm your brain today, this ...
1
vote
1answer
121 views

Number crossword puzzle

I'm trying to solve the following quiz from my daily quiz calendar (I have it in paper so I cannot give a link). It's like a crossword puzzle but with numbers. The empty cells should be filled with ...
6
votes
1answer
193 views

Fillomino with Sums: The Fillo That Smiles Back!

This puzzle is a Fillomino, with the special variant rule of Sums ("Cages") being applied. You might also notice that this particular fillomino is giving you a smile! This is my first time ...
9
votes
1answer
388 views

Trivia… sudoku

An entry in Fortnightly Topic Challenge #49: Pub Quiz Camouflage Please do not search the answers online (hence the no-computers tag), otherwise it would be too simple to solve this puzzle. I tried ...
5
votes
1answer
194 views

Double Ducky (or Fu-two-shiki)

There are two* logical, discrete ways to solve this Futoshiki puzzle, each with its own unique solution. You can solve it using the letters given, or use the numbers 1-5, but if you map the letters to ...
0
votes
1answer
99 views

Skyscraper 6x6 - unable to get next step

I tried to write a program to solve a Skyscrapers puzzle. Currently I'm teaching it to find the next steps out of nopes (values which cannot be present on the field) values and clues. So far the field ...
9
votes
1answer
170 views

Scrabblescrapers

An entry in Fortnightly Topic Challenge #48: Unusual tag mix In this puzzle, you are given a 5x5 grid that you need to populate with a word square, so that the rows and columns form words (as defined ...
14
votes
2answers
604 views

Now you're Packing with Portals #2: Hashtag

Place the colored shapes into the white area, without rotations or reflections, so that they fill it perfectly. The gray walls don't just block shapes, though - they act as portals! When you place a ...
7
votes
1answer
161 views

Nurikabe: Five Below

This puzzle is another one of my Nurikabes, and this time it's a smaller one made entirely of pieces that are 5 or less. Perhaps you can tell that making puzzles in this genre is slowly becoming my ...
5
votes
1answer
450 views

Skyscrapers 6x6 - Stuck at the end

I tried to write a program to solve a Skyscrapers puzzle. Until the last steps I always used the opposite clues. But I can't find a solution for the last cells. This is where I am: ...
42
votes
2answers
2k views

Now You're Packing with Portals #1

I was staring at my window last night, and daydreaming (nightdreaming?) about filling it with shapes. Suddenly, I was struck with inspiration for a new type of puzzle! Here's a fairly easy instance: ...
14
votes
1answer
471 views

Pento-Doku: Pentominous + Sudoku

Intended for Fortnightly Topic Challenge #47: Wacky Sudokus, but I was too slow making it... not for lack of trying, I assure you This puzzle is both* a Pentominous and a Sudoku**. Rules Solve the ...
3
votes
1answer
92 views

A Final Digitial Sudoku! - SS#14

An entry in Fortnightly Topic Challenge #47: "Wacky Sudokus" Other puzzles in this series Welcome to the final puzzle in this series! For more information about the series, see the first ...
12
votes
2answers
576 views

Unequal Curfew - Donut Hole

This is a Curfew variant. Curfew is a genre invented by Hempuli; I made a slight modification to give this variant. Rules of Unequal Curfew: Draw a loop that visits every circle. Each visit to a room ...
15
votes
1answer
451 views

This Sudoku Park iS LIT!

An entry in Fortnightly Topic Challenge #47: "Wacky Sudokus" The grid below is a normal Sudoku grid with normal Sudoku clues, but the completed grid also houses a Statue Park! The completed ...
12
votes
1answer
296 views

Sudoku: Odd Bonds

An entry in Fortnightly Topic Challenge #47: Wacky Sudokus. Edit: Clarified three of the rules. Rules: Normal sudoku rules apply. Inside the sudoku, there exists one "loop". The loop ...
9
votes
1answer
243 views

A Fractal Sudoku - SS#13

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

1
2 3 4 5
14