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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Tips on solving sudokus linearly
The last number of months I have been reading about numerous ways on how to solve Sudokus. So far I am familiar with obvious and hidden singles, obvious, hidden and pointing pairs, obvious, hidden and ...
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Sudoku Variant Puzzle
Some background first. The gimmick for this puzzle was inspired by a recent puzzle in a mathematics discord. As part of solving that problem I learned how to use a SAT Solver to generate cases.
During ...
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Pentadoku puzzle with only four clues (Jigsaw Sudoku)
Fill each empty square with a number so that every row, every column and every irregularly shaped region contains all the numbers 1, 2, 3, 4 and 5 each exactly once.
If you enjoyed this puzzle, you ...
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Fewest cages for unique Killer Kropki-less Sudoku
Inspired by Why are these 5s and 1/9 forced in by this Killer Sudoku cage under Full Kropki rules?
What is the fewest number of cages needed for a Killer Krpoki Sudoku to have a unique solution?
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How many Full Kropki Sudoku solutions are there?
Kropki Sudoku is a variant where all consecutive adjacent numbers must be marked with a white dot between them, and all adjacent numbers with a 1:2 ratio must be marked with a black dot. (This is just ...
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Why are these 5s and 1/9 forced in by this Killer Sudoku cage under Full Kropki rules?
I was busy creating a sudoku on the Interactive Sudoku Solver when I found that if I were to use the Full Kropki rules without any dots (i.e. no orthogonally adjacent squares may be consecutive or ...
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What is the next cell in this sudoku?
This is the NYT hard puzzle of the day on 14 July 2025
What am I missing?
...
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Peaceful Weighted Sudoku Chess Grid
To illustrate a valid solution, here is a first non-optimized at all solution of value 79
Let us fill a Peaceful Weighted Sudoku Grid with the maximum value with Chess pieces with the following rules:...
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Why is it incorrect to place a '1' in this Sudoku cell?
Why is the '1' flagged as wrong (even though 1 is not repeated in the row and column) when placed in the shown cell in this Sudoku puzzle?
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A pair of Kropki Sudoku puzzles
Warmup puzzle rules:
Kropki Sudoku puzzles add extra constraints to regular Sudoku, labelling all pairs of neighbouring squares which contain values where one is either twice the other or has a ...
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Sudoku with additional rule for the top row: alternating odd and even numbers
I made this sudoku that in addition to the usual rules shall be solved considering also the following rule:
the first row shall contain alternating odd and even numbers, the top-left element is odd.
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Sudoku with Special Rule(2)
Here is a sudoku, but with additional special rule.
The highlighted cells(which are gray) should have distinct number, from 1 to 9.
Could be quite hard… ;)
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“Afterlife” Sudoku puzzle
Fill each empty square with a number so that each row, column and 3x3 block contains all the numbers 1 through 9 exactly once.
To receive an upvote from me, you must completely solve this Sudoku.
For ...
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Sudoku puzzle with clues that are nicely positioned and nicely numbered
Beginner puzzle (suitable for people who are new to puzzle solving).
Fill each empty square with a number so that each row, column and 3x3 block contains all the numbers 1 through 9 exactly once.
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Arithmetic Sudoku
Consider this sudoku puzzle:
All normal sudoku rules apply.
But it has some extra conditions:
A,B,C must form an arithmetic series in that order. Equivalently, A+C=B+B.
D,E,F must form an arithmetic ...
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Sudoku with Special Rule
This is a Sudoku, with a special rule. Can you solve this?
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Can someone please help me in going forward with this Sudoku? [closed]
Please give ideas on how to move forward with this sudoku.
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Hint to start this sudoku puzzle
I can't find the first digit of this Sudoku puzzle, could you give me a hint?
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The Number PI V2. - Colombian Sudoku
Here’s a new Colombian Sudoku in honor of the number π.
Rules:
On the left board, there is a completed Sudoku. On the right board, the dots outside the grid (on the right) indicate how many cells in ...
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Triple Digits – killer sudoku + crossword
This is part 79 of the puzzle series Around the World in Many Days. Each part is solvable on its own.
Dear Puzzling,
Sometime during this trip I believe I have finally passed the milestone of 100 ...
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Jigsaw Thermometer Sudoku with no given numbers
Beginner puzzle (suitable for people who are new to puzzle solving).
To allow new users to solve this puzzle and earn reputation points, I encourage all users whose reputation is 200 or more to not ...
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A miniature Thermometer Sudoku (ThermoDoku)
Beginner puzzle (suitable for people who are new to puzzle solving).
Fill each square with a number (1, 2, 3 or 4) so that there are no duplicated numbers in any row, column or 2x2 block.
Numbers on ...
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¡¡¡ HNY 2025 !!! - Sudoku
This new year 2025 I bring you another special challenge! It's a 12x12 Sudoku, but with a twist (like last year): in addition to following the classic rules, the boxes of each color must have digits ...
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Middle of Nowhere
This is part 77 of the puzzle series Around the World in Many Days. Each part is solvable on its own.
Dear Puzzling,
This is a Yin-Yang sudoku. Fill the central 9x9 grid with the digits 1–9 so that ...
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Fill this partially-dotted Sudoku so that two sums are equal
Fill all 16 squares with a number so that every row, every column and every 2x2 box contains all the numbers 1, 2, 3 and 4 each exactly once.
Also the sum of the numbers in the six squares marked with ...
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What is the smallest number of clues needed to solve any standard 9x9 sudoku trivially [duplicate]
I define 'trivially' as being able to write every digit down in one operation, only considering that digit, without making pencil marks. The sort of problem you might give to a 5 year old. I hope the ...
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Help my dad solve the daily sudoku [closed]
It is rated "Very hard". He's usually able to solve them, but he was having a bit of trouble today. He asked me for help but I couldn't add what he had already written.
My dad's attempt:
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The Number PI - Colombian Sudoku
This is a very special Sudoku, created alongside the table on the right, in honor of the first 18 decimals of the number Pi. Here's how it works: the dots outside the board on the right indicate how ...
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PSE Advent Calendar 2024 (Day 11): A Sparkling Sudoku
This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2024. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door >
This is a ...
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Happy Thanksgiving! - Colombian Sudoku
In this new Sudoku variant, your goal is to solve the puzzle on the left following the standard rules: each letter from the word "THANKS" must appear exactly once in every row, column, and ...
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Sudoku variants #3: Schrödinger's Grave Remastered (8x8 grid)
Previous variant
Originally inspired by Cracking the Cryptic's video "The Graveyard of Schrödinger" (original gimmick by fjam)
Background
On Nov. 6, 2023 (1 year ago!), I posted the puzzle ...
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How can I progress on the Sudoku portion of "The Grave of Schrödinger" by fjam from here?
Almost 1 year ago, I posted the puzzle "Sudoku variants #1: Schrödinger's Grave (6x6 grid)", which was based off of a Sudoku variant created by fjam. While the original puzzle sadly turned ...
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8x8 Thermo Sudoku with no clues
Attribution: Me
Rules of Thermo Sudoku:
Numbers placed in cells overlaid by a thermometer must increase in value from the circle bulb to the other end.
Objective:
Fill in the 8x8 Sudoku such that ...
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A new game, but with colors
I want to show you a game I’ve created. I’m not sure if it already exists, since it’s so simple and nice that someone might have thought of it before, maybe with slightly different rules.
The rules ...
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Specific triangle sides in a grid
Fill each cell with an integer from 1-7 so each number appears exactly once in each
row and column. In each group of three cells, the three numbers must be valid lengths for
the sides of a non-...
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A Challenging Tetris - Dekadoku
Now I'm sharing this new and very difficult Dekadoku puzzle, which is truly beautiful. The color is decorative.
You already know the rules:
Place all the combinations of two-digit numbers (from 00 to ...
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Blue Clouds - Dekadoku
I greatly appreciate your support in this new challenge. I want to share this puzzle with you and hear your thoughts on the new rule I've added. What do you think? Thank you in advance for your ...
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A new nameless game
This is a new game I came up with the night after my birthday. It's so simple that I couldn't sleep just thinking about it. The rules are easy: you have to place all the two-digit combinations (...
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Simple but complex - Nonodoku
I'm back with more Nonodokus. This one is special because it combines the rules of a Jigsaw Sudoku with colored sections. The rules are simple: place the numbers 1 to 9 in each box or colored section ...
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World's smallest Sudoku!
I present today, the world's smallest sudoku!
It is just 3x3 pixels in size, making it just a mere 216 bits of data
It's currently right above! Pretending to be a full stop right here ↑
So my ...
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A sweet Nonodoku - Nonodoku
A new Nonodoku has arrived, the new adaptation of Nonogram to Sudoku. Remember, in this game, the numbers in each row indicate the relative order of the values in that row, but not their exact ...
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Determine the minimum number of numeric clues to make these mini-Sudoku puzzles have a unique solution
Below are three grid layouts for mini-Sudoku puzzles.
For each type (Square, L and T), determine the minimum number of numeric clues you (as puzzle composer) would have to place in the grid so that ...
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Grid network - Colombian Sudoku
This is a new Colombian Sudoku that I really enjoyed creating. The rules are the same as always: fill the Sudoku on the left, using the clues on the right. The number of points in a row of the table ...
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Minimum number of negative clues for a 9 x 9 Sudoku
It is known that an ordinary Sudoku with a unique solution must have at least 17 clues. A clue is a statement that a particular cell (i, j) must contain a particular value k.
But we could also ...
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Fill this Sudoku variant so that the sums of numbers in the outlined regions are all different
Place numbers in the grid so that each row and each column contain all the numbers {1,2,3,4,5} (each exactly once) and the sums of numbers in the outlined regions are all different.
Attribution: ...
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A checkered cross - Colombian Sudoku
This is a new Colombian Sudoku that I really enjoyed creating. It’s not very complex, but it’s quite beautiful. The rules are the same as always: fill the Sudoku on the left, using the clues on the ...
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Pinwheels - Colombian Sudoku
Here is another interesting Colombian Sudoku. The rules are as follows: complete the Sudoku on the left with numbers from 1 to 8 using the grid on the right. Keep in mind that the number of dots in ...
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Ying Yang 12x12 - Colombian Sudoku
Here is this week's Sudoku, my latest creation. It's a Colombian Sudoku that, despite its size, presents an extreme level of difficulty. Remember the rules: you must fill in the Sudoku on the left ...
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NONODOKU, A new game
Nonodoku is a new variant of Sudoku. In this game, the numbers in each row indicate the relative order of the values in that row, but not their exact positions. For instance, in the second row, if the ...
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Happy birthday, Bernardo - Colombian Sudoku
Bernardo, hb!!! This is a Colombian sudoku made in honor of my friend Bernardo Recamán, for his birthday. Complete the sudoku on the left so that each row, column, 3x3 square, and cell of the same ...
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