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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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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Most leads in a "difficult" Sudoku
Since "difficult" is undefined, let me define it arbitrarily: A Sudoku is difficult if it can't be solved by only considering singles (naked or hidden), the most basic solving strategy.
How ...
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Does every validly posed Sudoku have at least one solution and if not what is the minimum number of givens for it to be unsolvable? [duplicate]
Does every validly posed Sudoku (doesn't break any Sudoku rules so only no duplicate 1 to 9 in rows, columns or square) have at least one solution, and if not, what is the minimum number of givens for ...
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Sudoku on a Mobius Strip
Well we've done sudoku on keyboards, so the next step is obviously putting a Sudoku on a Mobius strip... of course...
I present, the world's very first MOBIUS SUDOKU:
Now this sudoku is going to be a ...
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How many Hoshi (Star Sudoku) are possible?
A gifted Sudoku booklet's Hoshi are (almost? - I did only spot checks) all identical, except for number permutation and leads.
An excuse for this would be if there were only one legit Hoshi. How many ...
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Sudoku.... On your keyboard?
Tired of solving Sudokus on paper? Look no further! The solution is, literally, under your nose.
Why use a 9x9 grid, when you can use your own QWERTY keyboard!
RULES:
Fill each row with the numbers ...
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Must any "hourglass" touching the hexagon, in a Sudoku Hoshi, contain the same number twice?
I think I found a law for Sudoku Hoshi (also called Star Sudoku) puzzles but since I did the proof more or less in my head, please check.
In case you don't know the rules, I quote:
Fill the grid so ...
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Japanese Streams Sudoku
TL;DR - it's a puzzle: In a previous puzzle, we presented a puzzle inspired by the recent Japanese Sums puzzle series at Grandmaster Puzzles which combined the Japanese sums cluing technique with a ...
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Japanese Odd Sum Sudoku
The Grandmaster Puzzles blog had a recent set of "Japanese sums" puzzles, and the mechanics of those puzzles gave me the idea for a Sudoku. It's not too hard, so I hope you enjoy!
The Sudoku ...
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Can you make a puzzle that looks correct until the very last piece?
Lately I've been enjoying a little game called Flow Fit: Sudoku.
It's basically sudoku meets jigsaw. You need to place the pieces into predetermined slots, and numbers cannot repeat in the same rows/...
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Next move in The Times Sudoku #12583
I'm completely stuck on how to move on with this Sudoku - what's the next number?
It's from The Times puzzles - number 12583 on 13/08/21
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Why can R1c3 not be a 4?
Take the following Killer Sudoku (from the app "Killer Sudoku" by Studio Goya LLC) I have been struggling with for the last few hours. "Penciled" numbers are my notes about which ...
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Is there a minimum number of clues that every sudoku puzzle has?
I've seen that the fewest clues on a Sudoku board has been proven to be 17 but I'm wondering if it's possible for every board to have some combination of 17 clues or, if not, if there is a proven ...
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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 ...
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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 ...
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"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 ...
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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 ...
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