# 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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### 9x9 Sudoku Puzzle

This is a standard 9x9 sudoku puzzle from a book I hope to publish:
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### Can every Sudoku puzzle be solved without brute force? [duplicate]

So I wrote up an algorithm for generating Sudoku boards, and it generated the following board: I was trying to solve it on my own and got stuck, which prompted me to try putting it in this website. ...
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### A tough sudoku puzzle

Here is a tough sudoku puzzle from my blog
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### Easy Sudoku Puzzle

This is an easy sudoku puzzle (no. 90) from my blog.
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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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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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### 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 ...
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### 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.
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### 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.
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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 ...
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### 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 ...
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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 ...
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### 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. ...
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### 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 ...
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### Next Move on this Sudoku Classic

What would be the next move? Link to this sudoku
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### 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 ...
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### 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 ...
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### 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 ...
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### Chessdoku Level 1 (beginner)

I just tested out a new type of puzzle here (sorry if there's any confusion with the titling) called Chessdoku! Welcome to level 1. Here's the grid: Your goal is to get one black and one white piece ...
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### Chessdoku Level 0 (trial)

Welcome to Chessdoku! It's like Sudoku but chess! This is level 0, so it's a trial run and will be fairly simple to solve (level 1 has been posted here). This puzzle is just for the concept. Here you ...
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