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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94
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2answers
6k views

This new puzzle type needs a name

I believe I have invented a new type of puzzle... What is its name? Colour-blind-friendly version available here. Begin by solving the 16x16 sudoku; each of the digits 1-16 must appear exactly ...
78
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1answer
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Empty sudoku puzzle

The rules are the same as for a normal sudoku puzzle. The only thing different is that instead of numbers for clues, you have greater than/less than (> <) signs between the cells. Have fun solving!...
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Happy Pi-Day! Try to solve this “PiDoku”

To celebrate the Pi-Day (3/14) adequately, a challenging math puzzle must not be missing. Rules: Fill in the numbers 1-9 exactly once in every row, column, and region. On top of that, you need to ...
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R.H.P.C. crossword puzzle

This is an entry into the Fortnightly Topic Challenge #36 I got a ticket to the Red Herring Puzzle Club in the middle of the street. There was just a guy giving them out, like some advertisement ...
60
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2answers
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Sudoku like you've never seen it before

I've spent this week trying to create a difficult logic puzzle which is a combination of two Sudoku varaints, 'Samuari Sudokus' and 'Pseudokus', and this combo is unlike anything you can find online. ...
58
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What is the maximum number of solutions a Sudoku puzzle can have?

I've seen Sudoku puzzles that can be solved two different ways. Referring to a traditional 9x9 grid: Is it possible for a Sudoku puzzle to have more than two solutions? If so, what is the maximum ...
54
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11answers
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Are there published Sudoku puzzles that require guessing?

I believe in a number of books I have read and solved myself, the introduction stated that guessing should never be necessary for any of the puzzles in the book. Instead, a handful of techniques ...
52
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2answers
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A 16 Clue Sudoku Puzzle (but the kings can't be in check)

An entry in the 19th fortnightly challenge... Above is a 9x9 "chess" board with some pieces already laid out, your goal is to fill the board completely, following standard Sudoku rules (i.e. every ...
50
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1answer
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Japanese Fusion Alphabet Soup

The Dish... ...is an intriguing blend, with a base of classic Western flavours, and a twist of the Orient at its heart. The Ingredients... ...are diverse and are combined in such an unexpected - dare ...
50
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1answer
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Self-referential Sudoku

I built this a while back but never had a good forum for it; this seems like the perfect spot to turn it loose. This is a 'traditional' Sudoku; cells are filled with numbers from 1 through 9, and all ...
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4answers
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Who am I??? Wait, isn't this a sudoku?

Jmw jrr qtlf tv ee M6SXr rro tr kz r tyr. Can you find out who I am? Hint 1: Hint 2:
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A Page of Puzzling

I found this puzzle page from a newspaper and found it absolutely confounding. The sudoku had question marks and other things all over it, the logic puzzle made no sense, the cryptic crossword was ...
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6answers
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Sudoku embedded in a Kakuro

In addition to standard Kakuro rules, the grey shaded cells must form a valid Sudoku solution. One sum in this puzzle has been corrected from 28 to 23. Fortunately, it was in a location that nobody ...
37
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1answer
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Didn't you ask me for a crossword?

An entry in Fortnightly Topic Challenge #forty-seven: "Wacky Sudokus" Here's that crossword you asked for... Sorry, what's that - you didn't ask me for a crossword?? TASK: Solve the puzzle ...
36
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11answers
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Sudoku net that is always solvable

A sudoku net is a 9x9 grid where every cell is either (blank) or has a cross (block). A random solved sudoku is chosen. The net is placed on top of the sudoku (in any of the 4 ways). We can only see ...
36
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4answers
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Sjudoku - in a world where 9 is replaced by 7

Sjudoku (sju = seven in Swedish). Rules similar to Sudoku applies: In each disk, the numbers 1,2,...7 should appear exactly once. No line may contain duplicate digits (note that there are lines in 3 ...
35
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3answers
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The Determinant Sudoku

The determinants of $2\times 2$ matrices are calculated this way: $$\det\begin{bmatrix}a & b \\c & d \end{bmatrix}=ad-bc$$ And here's the sudoku-determinant puzzle: What's the solution for ...
34
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What are the criteria for determining the difficulty of Sudoku puzzle?

What are the criteria for determining the difficulty of Sudoku puzzles? Is it a subjective estimation based on the author's experience, or are there any precise guidelines? For example, there are ...
33
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1answer
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MASTERING Sudoku

Fill the grid with letters M, A, S, T, E, R, I, N and G. Standard Sudoku rules apply. Additionally, the words on the right-hand side must appear in the given orientation (across/down). Each word ...
28
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1answer
477 views

George Orwell Sudoku

Here is a puzzle I created today. The title is "George Orwell Sudoku" Normal Sudoku rules apply. In every coloured group of three cells the middle digit must equal the sum of the other two ...
27
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2answers
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Pseudoku: A Game of Finding Order in Chaos

You are Pat Doe, a lowly Sudoku puzzle-maker eking out a living by producing hand-made Sudoku puzzles. After an exhausting eight hours, you've just completed your last Sudoku grid for the day. ...
27
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Can you solve my Chess Sudoku puzzles?

Rules Normal Sudoku rules apply except that instead of 9s you must place chess pieces. A puzzle can mix chess pieces, and in principle any piece may be used - although the rest of the constraints ...
26
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1answer
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This is a crossudoku

So, this is a crossudoku. It is the same as a sudoku - same rules apply. However, you have been given crossword-like clues for part of the numbers on the grid. Some of the clues may have multiple ...
26
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1answer
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A Puzzling Sudoku (Warning: Hot!)

An entry in Fortnightly Topic Challenge #47: "Wacky Sudokus" A Sudoku with an oddly familiar shape. Here's a Penpa Link. Rules: Normal Sudoku rules apply (Special) Thermometers: The ...
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4answers
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Another new puzzle type needs a name

For an example of how this type of puzzle works, see here... I believe I have invented another new type of puzzle... What is its name? Colour-blind-friendly version available here. Begin by ...
25
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2answers
3k views

Reversed Sudoku

Sudoku from Sudoku Solutions. Here's a Sudoku grid with all the obvious candidates removed. Your task is to re-supply the givens.
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788 views

A Minesweeper Sudoku

My brother created this puzzle, and he wanted me to post this here. Each 3x3 box contains three mines (those squares also have numbers in them). There are no mines in boxes containing a 1, 2, or 3. ...
25
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1answer
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The Blank Sudoku

An entry in Fortnightly Topic Challenge #47: "Wacky Sudokus" (h/t to Beastly Gerbil, whose 1,2,3... Trinary!!! puzzle provided inspiration for this puzzle) This puzzle is a normal Sudoku, ...
24
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3answers
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Ever heard of a W-Sudoku?

You may have heard of a type of Sudoku called an XV-Sudoku. In such a Sudoku, cells connected with an "X" must sum to 10 and cells connected with a "V" must sum to 5. In this W-...
24
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1answer
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Sudoku as Poetry: A Tag-Fusion Masterpiece

This is an entry in the 19th fortnightly topic challenge: Unconventional Tag Fusion. I wrote some poetry for you, but it's hidden within this sudoku. Solve the puzzle and find the poem. For those ...
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2answers
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What if I told you that guessing in Sudoku is very bad and might give you a bad karma?

Yesterday, I tried to solve a regular Sudoku puzzle. Of course, the Sudoku puzzle had a unique solution. But, I was feeling a little lazy, so, rather than solve the puzzle properly, I made guesses! At ...
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Introducing: Compoundoku!

Rules of Compoundoku: Solve both left and right Sudokus. In addition, the board below them is the Compound Board of both Sudokus. Each number on the Compound Board should tell either: (1) ...
23
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2answers
910 views

Slightly Odd Sudoku

Someone I find very trustworthy continues to insist that this is a valid Sudoku board. It's been a while since I've played, but surely there's a couple of things off here, right? Alright, so that ...
22
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4answers
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How do I solve the world's hardest sudoku?

This question is posted under the guidelines Don't worry too hard about restricting or regulating anything that isn't turning into a problem yet. If you don't agree that this question is on topic, ...
22
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2answers
969 views

Complaint at the PSE lounge

While walking through the PSE lounge, I noticed a piece of paper on one of the tables. Picking it up, I saw several things. The first, was a couple of sentences at the top: I love this place! But ...
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3answers
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There is a reason sudoku uses squares

There exists a 9x9 grid with the cells in one single row numbered 1-9 in order. The cells in the other 8 rows are initially empty. Note: The cells initially containing numbers can be in any one row;...
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Introducing Domidoku!

Come one, come all! Come see the new type of logic puzzle, the Domidoku! Here's a sample for all to try! The process is simple! First you solve the Sudoku and then you solve the Dominosa! ...
22
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1answer
380 views

Monument Valley Sudoku

Another Sudoku monstrosity from the brains of Yours Truly. No rules are given, part of the challenge is trying to work out what the rules are :)
21
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2answers
352 views

Tackling The Triptych

Normal Sudoku rules apply. Numbers on thermometers must increase, starting from the bulb end. Killer clues indicate the sum of three digits in a cage, which cannot include repeated digits. In columns ...
21
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1answer
458 views

Square Number Sudoku

Solve this diabolic Square Number Sudoku. Normal Sudoku Apply. Additionally, there are some rectangled area, in each area should be read as 1 number. The numbers must be SQUARE NUMBERS. There are: 1 1-...
20
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6answers
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The Unfinished Puzzle Section

Simply complete the sudoku and crossword, happy puzzling. Across 1. Achieved acclaim by being knowledgable about strange apron (3, 6) Down 2. Explode asteroid five to refrain from inactivity or ...
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2answers
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Sudoku in the third dimension (3D Sudoku)

People seemed to enjoy my last Sudoku variant puzzle - Samurai Pseudoku, so I spent this week making another! This one is going to require using logic you've never used before... The last one was a ...
20
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1answer
981 views

Sudoku in Technicolor!

An entry in Fortnightly Topic Challenge #47: "Wacky Sudokus" This puzzle consists of three overlapping Sudokus, coloured red, blue and green, so each cell will contain three digits, one of ...
20
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1answer
276 views

Arithmetic Progression Sudoku

In this puzzle, each square must contain a positive integer. All rows, columns and boxes must contain an arithmetic progression of length 9. Good luck!
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After here should I guess or is there a logic solution on Sudoku?

From this point is it necessary to guess or is it possible to find a logic solution?
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Tic tac toe - Sudoku: A variation in which the centre box defines the layout of the other boxes

I stumbled across this interesting variation of Sudoku the other day and thought I'd give it a try, it has however baffled me and I've been unable to progress past the very early stages. The puzzle ...
19
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1answer
1k views

Your Task Is to Create the World's Hardest Irregular Sudoku!

Ahem, let's formalize your task... 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 regular Sudoku is a $9 \...
19
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1answer
288 views

Compoundoku wants REALLY BIG and WACKY!

This is an entry for Fortnightly Topic Challenge #47: Wacky Sudokus. Rules of Compoundoku: Solve both left and right Sudokus. In addition, the board below them is the Compound Board of both Sudokus. ...
19
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1answer
436 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 ...
18
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2answers
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Why does generating a Sudoku work in lines, but not in a random pattern?

So, I'll preface this by saying that I am not 100% whether this fits better here or on SO. That said: I've been trying to generate Sudokus using a backtracking algorithm to fill in the whole thing. ...

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