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.
1,141 questions
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PSE Advent Calendar 2024 (Day 11): A Sparkling Sudoku
This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2024. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door >
This is a ...
- 2,809
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votes
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answer
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Happy Thanksgiving! - Colombian Sudoku
In this new Sudoku variant, your goal is to solve the puzzle on the left following the standard rules: each letter from the word "THANKS" must appear exactly once in every row, column, and ...
- 2,155
14
votes
2
answers
381
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A Simon Tatham's Galaxy puzzle
While playing Simon Tatham's Galaxies, I found this particularly difficult one. I did eventually solve it, but I found the solve path and final answer to be quite satisfying, so I thought I'd share it ...
- 3,600
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A mini sandwich - Dekadoku
A new puzzle, very interesting to solve. The rules are as follows:
Place all the two-digit combinations (numbers from 00 to 99).
In each row or column, no number can have the same tens digit.
In ...
- 2,155
0
votes
1
answer
207
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How can I progress from here on Minesweeper Advent Day 43? (Everyone's Favorite Shape Even Better)
It has honestly been some time (11 months, 2 weeks, and 1 day) since I have last posted one of my Minesweeper puzzles, and I would honestly like to get back into doing that with some more interesting ...
- 2,809
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votes
2
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Another Framework puzzle
Previous Framework
About Framework:
A Framework puzzle is similar to a Fill-in puzzle, except there is no rigid crossword-style grid, however there is a tradeoff with there being fewer hints given ...
- 2,809
6
votes
1
answer
821
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Fill the 4x4 grid with numbers to make eight arithmetic progressions
In the 4x4 grid below, fill each empty square with a number such that the numbers in each row form an arithmetic progression when read from left to right. Similarly, the numbers in each column form an ...
- 21.4k
5
votes
1
answer
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Sudoku variants #3: Schrödinger's Grave Remastered (8x8 grid)
Previous variant
Originally inspired by Cracking the Cryptic's video "The Graveyard of Schrödinger" (original gimmick by fjam)
Background
On Nov. 6, 2023 (1 year ago!), I posted the puzzle ...
- 2,809
4
votes
1
answer
185
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How can I progress on the Sudoku portion of "The Grave of Schrödinger" by fjam from here?
Almost 1 year ago, I posted the puzzle "Sudoku variants #1: Schrödinger's Grave (6x6 grid)", which was based off of a Sudoku variant created by fjam. While the original puzzle sadly turned ...
- 2,809
10
votes
1
answer
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8x8 Thermo Sudoku with no clues
Attribution: Me
Rules of Thermo Sudoku:
Numbers placed in cells overlaid by a thermometer must increase in value from the circle bulb to the other end.
Objective:
Fill in the 8x8 Sudoku such that ...
- 2,809
10
votes
1
answer
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a Latin inequality
This is a Futoshiki puzzle. You must put a single digit (1 through 7) in each empty square so that
each row and each column has exactly one of each digit, and
the inequality signs between adjacent ...
- 13.3k
9
votes
2
answers
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A new game, but with colors
I want to show you a game I’ve created. I’m not sure if it already exists, since it’s so simple and nice that someone might have thought of it before, maybe with slightly different rules.
The rules ...
- 2,155
16
votes
1
answer
645
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Otherworldly – Numberlink / Marching Bands
This is part 73 of the puzzle series Around the World in Many Days. Each part is solvable on its own.
Dear Puzzling,
The grey numbers here form a Numberlink puzzle. Draw lines in the grid using ...
- 81k
7
votes
1
answer
249
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A Challenging Tetris - Dekadoku
Now I'm sharing this new and very difficult Dekadoku puzzle, which is truly beautiful. The color is decorative.
You already know the rules:
Place all the combinations of two-digit numbers (from 00 to ...
- 2,155
7
votes
1
answer
441
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Blue Clouds - Dekadoku
I greatly appreciate your support in this new challenge. I want to share this puzzle with you and hear your thoughts on the new rule I've added. What do you think? Thank you in advance for your ...
- 2,155
23
votes
2
answers
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DEKADOKU, the new challenge
Thanks to @Beastly_Gerbil for the name. I'm sharing a new puzzle challenge with you. This is the first one I ever created, inspired by the Scientific American magazine cover from 1959. You can search ...
- 2,155
18
votes
1
answer
758
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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
3
votes
1
answer
235
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Determine what numbers must be filled into the shaded squares to make the grid (now with ten squares filled in) puzzle-ready
A 5x5 Latin Square is a 5x5 grid of squares in which each square contains one of the numbers 1 through 5 such that every number appears exactly once in each row and column. A partially completed grid (...
- 21.4k
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votes
1
answer
471
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Simple but complex - Nonodoku
I'm back with more Nonodokus. This one is special because it combines the rules of a Jigsaw Sudoku with colored sections. The rules are simple: place the numbers 1 to 9 in each box or colored section ...
- 2,155
17
votes
2
answers
774
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Can you find a grand tour of the rooms in this 12x12 grid?
Puzzle maven Nob Yoshigahara offered this puzzle in the September-October 2000 issue of MIT Technology Review, attributing it to a Professor Kotani. In the 4x4 complex of rooms above, two of the rooms ...
- 21.4k
15
votes
1
answer
583
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Fjord Explorer – a Nagareru crossword
This is part 72 of the puzzle series Around the World in Many Days. Each part is solvable on its own.
Dear Puzzling,
This is a Nagareru puzzle. Draw a single, non-intersecting, directional loop in ...
- 81k
10
votes
1
answer
553
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A sweet Nonodoku - Nonodoku
A new Nonodoku has arrived, the new adaptation of Nonogram to Sudoku. Remember, in this game, the numbers in each row indicate the relative order of the values in that row, but not their exact ...
- 2,155
11
votes
1
answer
503
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Bazaars and Bananas
This is part 71 of the puzzle series Around the World in Many Days. Each part is solvable on its own.
Dear Puzzling,
The black letters in this grid form a Hitori puzzle. Shade some cells in the grid ...
- 81k
6
votes
1
answer
187
views
Determine the minimum number of numeric clues to make these mini-Sudoku puzzles have a unique solution
Below are three grid layouts for mini-Sudoku puzzles.
For each type (Square, L and T), determine the minimum number of numeric clues you (as puzzle composer) would have to place in the grid so that ...
- 21.4k
5
votes
1
answer
158
views
Grid network - Colombian Sudoku
This is a new Colombian Sudoku that I really enjoyed creating. The rules are the same as always: fill the Sudoku on the left, using the clues on the right. The number of points in a row of the table ...
- 2,155
7
votes
1
answer
606
views
Fill this Sudoku variant so that the sums of numbers in the outlined regions are all different
Place numbers in the grid so that each row and each column contain all the numbers {1,2,3,4,5} (each exactly once) and the sums of numbers in the outlined regions are all different.
Attribution: ...
- 21.4k
7
votes
1
answer
356
views
A checkered cross - Colombian Sudoku
This is a new Colombian Sudoku that I really enjoyed creating. It’s not very complex, but it’s quite beautiful. The rules are the same as always: fill the Sudoku on the left, using the clues on the ...
- 2,155
8
votes
3
answers
823
views
Fill the grid with numbers to make all four equations true
Using all the numbers {1,2,3,4,5,6,7,8}, each exactly once, fill each empty white square with a number so that all the horizontal and vertical equations are true. The grey squares are not used.
...
- 21.4k
4
votes
4
answers
886
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Fill a grid with numbers so that each row/column calculation yields the same number
Using all the integers 1 through 9, each exactly once, put a number into each square in the grid below so that the result of each row and column calculation is 5.
All operations are performed "...
- 21.4k
11
votes
2
answers
1k
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The Master Tetrist
This is part 70 of the puzzle series Around the World in Many Days. Each part is solvable on its own.
Dear Puzzling,
This is a diagramless crossword with Tetris mechanics. Fill the grid by placing ...
- 81k
5
votes
2
answers
246
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Pinwheels - Colombian Sudoku
Here is another interesting Colombian Sudoku. The rules are as follows: complete the Sudoku on the left with numbers from 1 to 8 using the grid on the right. Keep in mind that the number of dots in ...
- 2,155
6
votes
1
answer
252
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Ying Yang 12x12 - Colombian Sudoku
Here is this week's Sudoku, my latest creation. It's a Colombian Sudoku that, despite its size, presents an extreme level of difficulty. Remember the rules: you must fill in the Sudoku on the left ...
- 2,155
12
votes
1
answer
320
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One number grid, two ways to divide it (Part 2)
Find a rectangular grid of the smallest area that satisfies the following:
Each cell contains an integer between 1 and 4 inclusive.
The grid follows the Fillomino rule:
When the cells are divided ...
- 17.1k
14
votes
2
answers
764
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One number grid, two ways to divide it
Find a rectangular grid of the smallest area that satisfies the following:
Each cell contains an integer between 1 and 3 inclusive.
The grid follows the Fillomino rule:
When the cells are divided ...
- 17.1k
16
votes
4
answers
2k
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The minimal Anti-Sudoku
Suppose we succumb to the urge to fill in a normal Sudoku grid as badly as we possibly can. That is, we strive to enter the digits from 1 to 9 nine times each such that no row, column or box contains ...
- 6,579
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NONODOKU, A new game
Nonodoku is a new variant of Sudoku. In this game, the numbers in each row indicate the relative order of the values in that row, but not their exact positions. For instance, in the second row, if the ...
- 2,155
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0
answers
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How many clues are sufficient to solve an X-Sudoku puzzle?
I've heard that for standard Sudoku a minimum of 17 clues are needed to solve a puzzle, but I imagine it might be slightly less in the variant X-Sudoku, because I assume there would be slightly fewer ...
14
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1
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426
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Stacked Nurikabe
My first go at puzzle construction! It's basically Nurikabe, but you have two boards stacked on top of each other, e.g. the first over the second, and the original constraints must still be satisfied ...
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Happy birthday, Bernardo - Colombian Sudoku
Bernardo, hb!!! This is a Colombian sudoku made in honor of my friend Bernardo Recamán, for his birthday. Complete the sudoku on the left so that each row, column, 3x3 square, and cell of the same ...
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votes
1
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How to finish off a sudoku with lots of options?
The Sudoku below has difficulty approx 4/10, so it's supposed to be quite simple.
However, I'm stumped.
Can someone give me some tips here? I'm not looking for the solution, only strategies for how I ...
- 1,358
1
vote
1
answer
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Shikaku grid deduction puzzle
Japanese publisher Nikoli produces this geometric logic puzzle. Can you divide this grid into rectangular and square pieces such that each piece contains exactly one number and each number reflects ...
- 5,231
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1
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🧩CRYPTICROSS🧩
You’ve been framed for the heist of a famous painting! Can you sort out the clues and come up with a convincing alibi?
Solve it on Penpa+!
Note: Although not necessary to solve this puzzle, the ...
- 1,536
14
votes
1
answer
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Double Grid Miracle Sudoku
A miracle sudoku is a name of a sudoku given with what looks to be so minimal information that it at first seems impossible to work, first started and mentioned in this video by Cracking the Cryptic. ...
- 2,967
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Mini spiral - Colombian Sudoku
Fill in the sudoku on the left so that each column, row, box, and section of the same color contains the numbers 1 to 9. The dots indicate how many numbers in the corresponding row or column of the ...
- 2,155
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votes
2
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Explain This Star Battle Clue
I'm playing a 2-star 9x9 grid game. The app provides incremental clues when requested.
In this scenario, the clue states "the green region cannot be finished."
I'm just not seeing it, nor ...
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1
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Solid border Yin-Yang
Yin-Yang is a grid deduction puzzle with the following rules:
Fill each cell with either a black circle or a white circle.
All circles of a given color must form a single orthogonally-connected ...
- 3,503
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votes
1
answer
414
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Colombian Sudoku, Cows and Bulls again…
Fill the sudoku on the left so that each column, row, box, and colored box of the same color contain the numbers 1 to 9. The dots show how many numbers in the row or column of the grid on the right ...
- 2,155
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What is the name of this puzzle type? How to create one? nxn grid where you select n cells with different numbers
I want to create a specific puzzle, but I'm wondering if it already has a name, and if I can find some pointers on how to make it hard.
I have a NxN grid filled with numbers going from 1 to N.
I want ...
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Fill the triangular grid using the digits 1-9 subject to the constraints provided
Fill the grid using the digits 1-9 four times each. No row or column can contain the same digit more than once. The total of each row and column is provided, as well as clues to the numbers forming ...
- 21.4k
4
votes
3
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Eliminate some numbers so that each of the three rows contains the numbers 1 through 9 each exactly once
Beginner puzzle
This puzzle is intended to be suitable for people who are new to puzzle solving.
Clarification: Both experienced solvers and new solvers are welcome to post solutions to this puzzle.
...
- 21.4k