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.

Filter by
Sorted by
Tagged with
1 vote
2 answers
238 views

9x9 Sudoku Puzzle

This is a standard 9x9 sudoku puzzle from a book I hope to publish:
user avatar
0 votes
0 answers
56 views

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. ...
user avatar
3 votes
1 answer
278 views

A tough sudoku puzzle

Here is a tough sudoku puzzle from my blog
user avatar
-2 votes
1 answer
222 views

Easy Sudoku Puzzle

This is an easy sudoku puzzle (no. 90) from my blog.
user avatar
6 votes
1 answer
779 views

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, ...
user avatar
0 votes
1 answer
110 views

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?
user avatar
28 votes
1 answer
686 views

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 ...
user avatar
  • 23.9k
11 votes
1 answer
507 views

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 ...
user avatar
  • 1,578
16 votes
2 answers
1k views

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 ...
user avatar
  • 6,569
4 votes
2 answers
469 views

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 ...
user avatar
0 votes
1 answer
125 views

Is there any sudoku logic on 6's?

I find this sudoku puzzle very difficult. I think there is some logic on 6's.
user avatar
0 votes
2 answers
105 views

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.
user avatar
2 votes
2 answers
299 views

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 ...
user avatar
15 votes
2 answers
870 views

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 ...
user avatar
  • 33.7k
3 votes
2 answers
359 views

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 &...
user avatar
  • 31
12 votes
1 answer
428 views

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 ...
user avatar
  • 1,283
6 votes
3 answers
881 views

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 ...
user avatar
9 votes
2 answers
278 views

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 ...
user avatar
3 votes
1 answer
200 views

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 ...
user avatar
0 votes
1 answer
138 views

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 ...
user avatar
33 votes
2 answers
3k views

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 ...
user avatar
3 votes
1 answer
176 views

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 ...
user avatar
23 votes
2 answers
2k views

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 ...
user avatar
17 votes
2 answers
2k views

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 ...
user avatar
9 votes
1 answer
301 views

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 ...
user avatar
  • 23.9k
17 votes
1 answer
495 views

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 ...
user avatar
  • 23.9k
5 votes
1 answer
1k views

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/...
user avatar
  • 943
3 votes
1 answer
157 views

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
user avatar
  • 33
2 votes
1 answer
259 views

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 ...
user avatar
  • 123
3 votes
1 answer
270 views

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 ...
user avatar
  • 31
14 votes
2 answers
393 views

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 ...
user avatar
  • 23.9k
16 votes
2 answers
728 views

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 ...
user avatar
  • 23.9k
7 votes
1 answer
350 views

"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 ...
user avatar
  • 3,681
7 votes
2 answers
538 views

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 ...
user avatar
  • 15.1k
5 votes
1 answer
265 views

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 ...
user avatar
  • 617
0 votes
1 answer
113 views

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.
user avatar
2 votes
1 answer
182 views

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.
user avatar
12 votes
1 answer
338 views

9x9 Sudoku Slitherlink Hybrid

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 ...
user avatar
  • 617
9 votes
1 answer
201 views

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 ...
user avatar
  • 7,997
5 votes
1 answer
195 views

Sudoku + Slitherlink

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 ...
user avatar
  • 617
6 votes
1 answer
132 views

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. ...
user avatar
  • 6,569
10 votes
3 answers
938 views

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 ...
user avatar
  • 123
1 vote
1 answer
132 views

Next Move on this Sudoku Classic

What would be the next move? Link to this sudoku
user avatar
4 votes
3 answers
821 views

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 ...
user avatar
8 votes
2 answers
421 views

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 ...
user avatar
20 votes
1 answer
547 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 ...
user avatar
  • 23.9k
5 votes
1 answer
253 views

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 ...
user avatar
13 votes
1 answer
451 views

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 ...
user avatar
9 votes
1 answer
423 views

Trivia... sudoku

An entry in Fortnightly Topic Challenge #49: Pub Quiz Camouflage Please do not search the answers online (hence the no-computers tag), otherwise it would be too simple to solve this puzzle. I tried ...
user avatar
  • 4,733
8 votes
5 answers
549 views

Checking for cheating in a Sudoku puzzle?

I am writing a puzzling site at the moment, which will naturally include Sudoku. It struck me that there will be potential users that will try to cheat when solving puzzles. By cheat I mean that they ...
user avatar

1
2 3 4 5
7