Questions tagged [sudoku]
A Sudoku is a puzzle consisting of a grid to be filled with symbols, such that each constraining unit contains each symbol exactly once. The typical example is a 9x9 square to be filled with the numbers 1 to 9, where the constraining units are rows, columns, and 3x3 blocks.
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Given an ordinary sudoku puzzle how would you convert it into an irregular sudoku?
I'm trying to create a puzzle like the one below (image snagged from puzzlephil.com).
I know how to generate and solve sudoku 3x3 variation via C#, and I'm now trying to add
a new variant, irregular ...
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What are the largest and smallest numbers in decimal base in this special Sudoku?
I have constructed the following hexadecimal 16×16 sudoku in this site:
The rules are like 9×9 sudoku tables (each number and letter should repeat only one time in each column, row, and 4×4 ...
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Roughing It (Once More)
This is part 36 of the puzzle series Around the World in Many Days. Each part is solvable on its own.
Dear Puzzling,
The numbers in blue form a Tapa puzzle. Shade some cells in the grid so that the ...
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Next Sudoku Number
Here is a sudoku puzzle coming from this magazine
I found that B5 and B6 can only contain 6 and 7. 8 cannot be in B5 because D1 would be a 8 and neither B3 not C1 could be a 8.
I thought it would help ...
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Two favorites combined: A Crypto Sudoku
Below is just a plain old sudoku. However, the clues given are a little bit different than usual. It's your job to use them properly. Note: Not every letter makes the same digit, nor every digit is ...
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Is the Parity Sudoku solvable?
I have a new kind of grid puzzle (you could call it a variant of sudoku) I will be calling a Parity Sudoku.
Parity Sudoku is played on a 6x6 grid of integer cells with numbers ranging from 1 to 6. It ...
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Maximize "sudoku" occurrences in a sudoku
How often at most can "Sudoku" occur in a valid (9x9) sudoku?
create a valid sudoku
replace (all occurrences of) 5 of the numbers by the 5 letters in "sudoku". (and leave the ...
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Can you embed a 4x4 Sudoku inside a 16x16 Sudoku?
In an earlier question (Can a standard Sudoku puzzle contain a miniature Sudoku puzzle?), I asked whether a miniature 4x4 Sudoku could be embedded in a standard 9x9 Sudoku.
Inspired by the following ...
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Sandwiches by the Seaside
This is part 31 of the puzzle series Around the World in Many Days. Each part is solvable on its own.
Dear Puzzling,
This is a sandwich sudoku puzzle. Each of the eight different letters in the grid ...
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Can a standard Sudoku puzzle contain a miniature Sudoku puzzle?
The following is an example of "Miniature 4x4 Sudoku puzzle" in which the goal is to fill each empty square with a number (1, 2, 3 or 4) so that there are no duplicated numbers in any row, ...
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NYT Sudoku Medium
I have always done Sudoku on paper and can always do mediums and usually hards. I've started doing the NYT Sudoku online and too often have trouble with the medium. At this point in this particular ...
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Sudoku android App - Difficulty Level
I have an android sudoku app and I'm doing the following to check if the generated sudoku is unique:
Remove a number
Run a solver
Check if the puzzle is still unique
Repeat until solver is unable to ...
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Orthogonally connecting even sudoku digits avoiding squares
Is there a way to complete a sudoku where you have to make sure all even digits are orthogonally connected to all the others, while avoiding 2x2 squares of even digits?
It is known to be possible when ...
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Can experienced players tell when a Sudoku was randomly generated? Or if it's a shuffled version?
I'm trying to make a simple classic Sudoku game in JavaScript, and I'm wondering what considerations I should have in how experienced players might interpret the generated puzzles. I'm not very ...
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Hard Sudoku: hint for next number
I tried a hard sudoku and I can't figure out what the next number is. I tried some online tools without any success (I don't want to have the final solution without any explanation).
I would be very ...
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Explanation why next cell has to be a certain value
I'm an absolute beginner and was stuck at the first puzzle of Sven's Sudoku Pad. I reached the following board state, where I noted for every cell which values were possible:
After a while I simply ...
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Why can't a 1 go in this field
I've moved onto "expert" sudoku's in my app (Sudoku.com on IOS) and whilst I am getting by solving some, others I'm having a hard time with.
With this one, I used a hint so the AI could note ...
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Behind Great Walls
This is part 10 of the puzzle series Around the World in Many Days. Each part is solvable on its own.
Deаr Puzzling,
This is a word search puzzle with a wildcard character. There are eight unique ...
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Horological Horrors
This puzzle is part of the Monthly Topic Challenge #6: Is it really that [time] again?.
I was visiting my grandfathers workshop one day, when he received a call and had to run out for a bit. He told ...
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How many Nonconsecutive Sudoku solutions are there?
Consecutive Sudoku is a variant with the additional rule that orthogonally adjacent numbers are consecutive if and only if there is a dot/bar on the line between them. A Nonconsecutive Sudoku is one ...
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Unsure how to continue Sudoku solve/apply Y-Wing strategy
I am not new to solving a sudoku board, but I do not have a lot of experience with harder boards and more advanced strategies (I am able to solve a "hard" board in under 10 minutes, on ...
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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 ...
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PSE Advent Calendar 2022 (Day 1): A festive Sudoku
This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2022. The accepted answer to this question will be awarded a bounty worth 50 reputation.Next Door >
Rules:
Normal Sudoku rules ...
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Consecutive Sudoku 6x6
I honestly don't know how to start... so I'm just looking for how to start, ie is there a number that we know where it has to go and why?
In addition to standard Sudoku rules, numbers on either side ...
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Non-separable sudoku numbers
The standard rules for sudoku say that you have a 9×9 grid and need to put in every digit from 1 to 9 in a way that each digit occurs exactly once in each row, column and 3×3 box.
So the grid can be ...
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The Universe's Secret
To find the universe's secret, first solve the Sudoku variant with #s 1-7 only.
No number may be repeated on any diagonal. No numbers go in the squares with red or green dots.
Then use the solution ...
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Sudoku pairs diagonal corners
Is it correct to deduct that the [4,8] (blue) pairs in diagonal corners, project [4,8] on the opposite (green) corners, such that the other values (1 and 6) could be eliminated?
(*) I'm not sure if ...
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5×5 sudoku with special properties
Complete the network with numbers from 1 to 5 so that the same number does not occur in any line, column, specially marked figure and on both diagonals.
I tried to start with a number that I know for ...
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How do I solve this sudoku without guessing
I am fairly new to Sudoku and couldn't find how to progress with this one without guessing.
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Build your own puzzle!
This grid contains 3 puzzles all in one; 0h n0, a Crossword and a Wordoku (Sudoku with letters)...
...but first you'll need to build it.
0h n0
Cells can 'see' other blue cells in the same row and ...
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Solving Sudoku purely by logic: why does this X-cycle choose this cell?
I've been reading several articles on difficult Sudoku puzzles and whether "guessing" is ever acceptable. The attached image shows the stage I reached using only deduction but at this point ...
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Objects in Mirror
This puzzle is part of the Monthly Topic Challenge #1: Restricted Title: xkcd 1xxx and is based on https://xkcd.com/1125/.
[Penpa link at the bottom, if you want to skip the story]
Objects in Mirror ....
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My Pentadoku puzzles (Jigsaw Sudoku)
In each of the following puzzles, fill the empty squares with numbers so that every row, column and irregularly shaped region contains the numbers 1, 2, 3, 4 and 5 exactly once.
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9x9 Sudoku Puzzle
This is a standard 9x9 sudoku puzzle from a book I hope to publish:
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Binary Sudoku Puzzle
The rules of Binary Sudoku are quite simple. It is very similar to regular Sudoku, except here we try to fill a 9x9 board with only black and white tiles following the below rules:
Every row, column, ...
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Is X-Sudoku easier to solve than classic Sudoku [closed]
X-Sudoku has extra rule for diagonals which give extra hints for diagonal cells. Does this implies that solving X-Sudoku puzzles are easier than classic Sudoku puzzles?
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PSE Advent Calendar 2021 (Day 20): Candy Cane Sudoku
This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2021. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door >
So I was ...
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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 ...
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The Golden Age of Sudoku
Rules:
Each cell contains one of the following symbols: A23456789TJQK. No two cells in the same row or column have the same symbol.
The grid is divided into 11 square regions of different sizes. A ...
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Very close to solve the sudoku puzzle but yet not solved
I found an X-Wing pattern using 1's on r29c48 and eliminated the 1's on r1c8, r3c8, r7c8, and r3c4. Lots of elimination but that was not helpful for me to crack it.
I think I am very close to solving ...
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Is there any sudoku logic on 6's?
I find this sudoku puzzle very difficult. I think there is some logic on 6's.
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Which sudoku logic should I apply here?
I was able to eliminate 1 in r8c1(in short selected cell) using Finn X wing using 1's on r17c15 and Finn is on r7c3. But it seems like that logic is not enough to make it to half way of this sudoku.
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Missing logic in sudoku puzzle
I got stuck in the given sudoku puzzle. I can't find any logic to put a number in the empty block. I am playing classic sudoku Android puzzle app.
Maybe it's a XY wing or empty rectangle or any other ...
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Imagine a Sudoku with Text-Only: A Gridless 6x6 Antiknight Antidouble Sudoku
Imagine the following Sudoku:
Imagine the Sudoku has a 6x6 grid with standard boxes, 2 rows and 3 columns each; and standard digits, 1 to 6.
Imagine it has an antiknight rule: identical digits cannot ...
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Impasse with this Sudoku puzzle
This was an advanced puzzle, and I managed to take it as far as possible. Now, I am stuck. I have tried many advanced patterns to no avail. I could use some pointers. It's from an IOS app called &...
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What are the rules to my Sudoku?
I made a Sudoku variant puzzle pictured here:
Your puzzle is to figure out what the rules for the puzzle I created are.
The puzzle has a single unique solution so if your rule-set allows more than ...
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Help solving this sudoku?
I went up in difficulty on my Sudoku app (Enjoy Sudoku app on Android). I keep getting mostly through them; however, I keep getting stuck towards the end of the puzzle. An example is shown below. Can ...
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Orthogonal Sudokus
This a Sudoku puzzle created by Paul Vaderlind.
Fill each cell with 2-digit numbers from 11 to 99 (without the digit 0) such that
The first digits represent one regular Sudoku grid.
The second digits ...
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