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Puzzles such as Sudoku or Kakuro, where the final state of a pre-existing grid must be deduced logically through clues placed within and/or around the grid. For puzzles where you are given a list of clues which can be used to compose a grid to solve them logically, use the [logic-grid] tag instead.

4
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2answers
37 views

Sto-stone puzzle

Sto-stone is a puzzle made by Nikoli. Here are the rules: You must color the cells with black with the following rules: There are rooms enclosed in bold lines. The number on the room shows the ...
15
votes
2answers
256 views

Unusual Kakuro Puzzle

Entry into Fortnightly Topic Challenge #38: Reusing Information 1 This puzzle sort of looks like a kakuro puzzle but there doesn't seem to be any sums. Figure out how this puzzle works and solve the ...
13
votes
1answer
283 views

HAISU with a twist

HAISU is a grid-deduction puzzle designed by this site's very own TheGreatEscaper. To quote them: HAISU is a portmanteau of three Japanese words - 'hairu', to enter, 'su', number, and 'hausu', an ...
8
votes
1answer
157 views

Unusual Sudoku Puzzle

Find the solution to this Sudoku puzzle. The only problem is there aren't any normal Sudoku clues. Instead there are only some cryptic clues. What is the solution and how does the puzzle work? Edit: ...
28
votes
1answer
528 views

Pikurossword, or: Three-in-One

This is an entry into the Fortnightly Topic Challenge #36. [edit: i hope this wasn't too bad for my first puzzle here! let me know how i did :)] The answer to this puzzle should answer the question: ...
37
votes
1answer
1k views

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 ...
37
votes
2answers
732 views

Circuit Diagram

An entry to Fortnightly Topic Challenge #35: Restricted Title 1 - based on the following xkcd. Circuit diagrams can be quite difficult to understand, so here are some documents that will hopefully ...
23
votes
2answers
725 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 ...
20
votes
1answer
566 views

Snakes on a Plane! 2

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Inspired by the title of this xkcd comic. Snakes ... on a plane ... again ... This time 2 specimens of a huge unknown type of snakes ...
15
votes
1answer
512 views

Barrel - Part 1

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Title based on the very first xkcd. Continued in Barrel - Part 2, Barrel - Part 3, Barrel - Part 4, and Barrel - Part 5. You manage a ...
14
votes
2answers
448 views

Hitchhiker's guide to Scrabble

I was working at My God, it's full of stars! puzzle, when a sudden realisation came into my head: that I have a friend, who is also an astronaut, and that I have an appointment with him! We were ...
27
votes
5answers
2k views

Making Things Difficult

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Factoring the Time Think fast! If you're looking for meaning, these clocks have some for you. Keyboards are Disgusting Gunky ...
23
votes
1answer
480 views

Stingray Nebula

An entry in Fortnightly Topic Challenge #35: Restricted Title 1. Inspired by the title of this xkcd comic, but in no way related or affiliated beyond the shared name. This is the stingray nebula: ...
11
votes
1answer
400 views

An Incomplete Puzzle

I'm sorry to offload some of my work as the puzzle creator on to you solvers. (No, I'm not.) At least there's only one clue missing, right? EDIT: When the puzzle is ready to be solved, there will be ...
11
votes
2answers
383 views

Slitherlink with crossing allowed

In a Slitherlink puzzle, you need to construct a single closed loop connecting points of a grid such that each number clue counts the number of adjacent loop segments. Normally, a Slitherlink puzzle ...
13
votes
1answer
290 views

Hey! Wake Up! Look At This Grid Puzzle!

The grid is divided into rooms, though some are wibbly-wobbly weird-shaped. Hey, aren't these normally supposed to be blocks? What should the title of this puzzle really be? ...
19
votes
1answer
1k views

Chess Connect Puzzle

I made up a new logic puzzle based on the games Numberlink and Chess, and thought it ended up rather interesting. The solution, as usual, is unique. The starting and ending positions of 7 chess ...
24
votes
2answers
376 views

Popularity Within a Target Audience

This is a metapuzzle with four component puzzles and a final meta. Creations of CSIRO The Australian research institute CSIRO is notable for producing inventions such as gene shears, the insect ...
6
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0answers
250 views

Grandma's keynote

Found this note which is addressed To my grandma, in her chest Since she's passed now, here's my quest.. What tickled her interest? And who invited her as guest?
19
votes
8answers
1k views

Shortest way from B to A

Spent most of my life out at sea I've crossed a shark or two – or three Stayed calm – a skipper brave and tough Yet one of them did call my bluff Gorged on my leg with glee Not yet ...
19
votes
0answers
1k views

One 'double agent' two-step on a waltzing floor

I'm in a jam – cornered I am! – No clue 'bout where to go Here's what went down, a pretty gown Some wine, a French chateau She whispered underneath her breath "Come dance with me and ...
8
votes
4answers
474 views

The Knights and the Hounds

(With thanks and congratulations to Lee Leon) We rejoin our heroes several days after the events of The Knights' Gift, at the head of a pack of enormous staghounds, 1000 strong. Such a pack ...
32
votes
2answers
3k views

I've been everywhere, man

I am a knight facing a plight My dearest one of all Lives in a tower and won’t come out Unless her name I call I went to pick her up today And though my mind was set To do so, as I ...
6
votes
1answer
149 views

Latin Square Puzzle - Difficult

Follow on puzzle from the introductory Latin square puzzle post. The rules It’s a Latin square like sudoku, so there must be the numbers 1-9 exactly once in every row and column. Notice that each ...
7
votes
1answer
215 views

Latin square puzzle

This is a sudoku-esque puzzle I came up with when trying to solve some harder sudoku. The rules It’s a Latin square like sudoku, so there must be the numbers 1-9 exactly once in every row and ...
62
votes
2answers
4k views

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 ...
8
votes
1answer
161 views

Backwards Boggle

I came up with a fun little 1-player puzzle for myself to do when bored. Pick 5-6 words, preferably words that share a good number of letters, and try to create a Boggle board containing all of those ...
6
votes
2answers
229 views

How does one go about creating a new grid-deduction puzzle?

The grid-deduction tag covers puzzles like Sudoku, Kakuro, etc. where the goal is to fill in a grid of numbers [/letters/colours] in a unique way by logical deduction from some predetermined rules and ...
8
votes
1answer
219 views

Partiti : solve this new type of puzzle

These are puzzles similar to Kakuro, which is the creation of a friend of mine whom I met last year: Rules: Place one or more digits from 1 to 9 in arbitrary order in each empty cell, such that a ...
4
votes
4answers
646 views

Flow Free Favourites

Recently, I have been amusing myself with the interesting puzzles provided by the excellent Flow Free puzzle app. Since I couldn't find a way to bookmark my favourite puzzles, I took up a habit of ...
19
votes
1answer
1k views

Make numbers 0 - 11 using the digits 2, 0, 1, 8; BUT

... seriously, this is definitely NOT that "kind of puzzle"! ;) So let me create this puzzle to freshen you up! It is inspired by a meta question: Yet another 2018 puzzle. Put the digits 2, 0, 1, ...
4
votes
1answer
104 views

RPS Trinity - Teddy and Her Ribbon

The Rules of RPS Trinity: You are given a board with its tiles colored either black or white. Put Rocks (denoted by letter R), Papers (denoted by letter P), and Scissors (denoted by letter S) on ...
27
votes
1answer
801 views

You go wherever you go today

A conclusion to my entries in the Fortnightly Topic Challenge #32: Grid Deduction Hybrids. This metapuzzle incorporates the three previous puzzles in this series: Desert Irrigation Project I am an ...
7
votes
1answer
460 views

Two Christmas trees

To each Christmas tree : Put two $+$, two $-$, and two $×$, to the yellow triangles. in a row, there must be different operators (so between $[2,0,1,7]$ all $3$ operators must appear) $A - B$ means $|...
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votes
2answers
688 views

Try to design a uniquely solvable masyu

Warning: extreme difficulty Does there exist a 6x6 masyu puzzle with one black pearl in each row/column (without any white pearls) which is uniquely solvable? What about for 7x7 grids? In fact, what ...
37
votes
1answer
2k views

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 - ...
6
votes
1answer
339 views

Hashiwokakero Puzzle

Rules: Connect islands (the circles with numbers) with as many bridges as the number in the island. Bridges can go only in a straight line horizontally or vertically. There can be no more than two ...
5
votes
1answer
158 views

Sums to a square number

arrange the numbers 0 to 9 in the circles below, following these rules : Every row of 3 or 4 circles sums to a square number. Every diagonal of 3 circles sums to a square number. Every green circle ...
14
votes
2answers
723 views

25x25 slitherlink puzzle

Basic rules Form a loop using the dots (so, by joining orthogonally adjacent dots) such that a number N is surrounded by exactly N segments of the loop. Here's a tutorial puzzle and its unique ...
12
votes
1answer
244 views

Difference or addition on a rose petals

Arrange the numbers 1 to 20 onto the rose petals using these rules : Yellow petals contain odd numbers, white petals contain even numbers. The outer petals are the difference or addition of the inner ...
7
votes
1answer
192 views

Connected circles which sum of any two of them which are adjacent is a triangle numbers

Arrange numbers 1 to 36 to the small circles and ovals, with rules: sum of any two of them which are adjacent is a triangle numbers. The first 12 Triangle numbers are 0, 1, 3, 6, 10, 15, 21, 28, 36, ...
10
votes
1answer
1k views

Sudoku with chess queen rules

This is a unique sudoku. With Rules : Common sudoku rules apply. Numbers 1,2,3 have an additional rule, they are also chess queens. If all others numbers removed, the 1s do not attack each other ...
14
votes
1answer
647 views

Masyu jigsaw puzzle

Here's a masyu puzzle for you. The rules are as follows Draw a single closed loop which does not cross or touch itself. The sections of the loop run horizontally or vertically between the ...
13
votes
2answers
505 views

Double n-queen puzzle, with sudoku rules

Put 9 blue queens and 9 pink queens, with rules : If the blue queens removed, each pink queens do not attack each other. If the pink queens removed, each blue queens do not attack each other. Each 3×...
5
votes
2answers
754 views

Special Sudoku, with windows pattern

Solve this Sudoku, with rules : Every blue square means, it is the left-top of a 3x3 block with each numbers [1 to 9] appearing only once there. There is only one unique solution. Check the example. ...
3
votes
1answer
186 views

Fill the table so every consecutive 3 numbers sums to 50 or 100

Arrange numbers 1 to 40 to the table with rules: Multiple of 4 Numbers and some perfect square numbers are already there as guide. Every 3 consecutive numbers with pattern white-yellow-white, must ...
7
votes
1answer
741 views

Solve this Subtraction sudoku!

This is subtraction sudoku. The rules are basically the same as common Sudoku, but with a few additions. In the row, the number in the orange box is the difference when its left side (sum of 3 ...
4
votes
2answers
315 views

Find the ? in this grid

Find question mark in this grid with numbers. csv version: 9,6,7,3 2,4,7,6 4,1,5,8 3,0,3,? Hint: You use all numbers to find ? and it is much more simple ...
7
votes
2answers
658 views

Fill numbers to the star shaped puzzle

Fill in all the blank circle with numbers 1 to 6, so : Each lines of 6 circles, contains 6 different numbers. Each corner (consist of 3 greens circle) sums to 11. There is only 1 unique solution.
9
votes
2answers
449 views

Tetromi-nuri-doku

Note: This puzzle was inspired by the one here, by Mike Q. Every square in the grid above, when the puzzle is complete, has a number between 1 and 9 in it and either is shaded or is not. Each 3x3 ...