Questions tagged [grid-deduction]

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.

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5
votes
1answer
170 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 ...
15
votes
2answers
869 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
258 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
274 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 ...
19
votes
1answer
772 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
538 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
782 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
189 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
829 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
323 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
786 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
506 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 ...
10
votes
1answer
467 views

5x5 Grid with all two digit numbers

There is a $5\times5$ grid where you are supposed to put all two digit numbers which consist only of the digits $1$ to $5$, namely $11,12,13,14,15$,$21,22$,.... The task is to put all these two digit ...
9
votes
2answers
246 views

4 pieces into a big slitherlink

Arrange the 4 pieces into a big slitherlink. To help you arrange it, First find the solvable small slitherlink then put it in the bottom-left position. 1st piece 2nd piece 3rd piece 4th piece
7
votes
3answers
496 views

Slitherlink the second

Find the solution to this slitherlink puzzle that I came up with: This one's even smaller!
9
votes
1answer
470 views

Ripple effects: A suite of puzzles and conundrums

Best explained here. Basically there are two rules: fill in each region with the numbers 1 to N, where N is the size of that region two numbers, both K, cannot both be in the same row or column if ...
6
votes
4answers
1k views

Filling the board with 0s and 1s

You are given a $9\times9$ grid board. You have 40 "$1$"s and 41 "$0$"s. You can put these numbers wherever you want on the board. After that, you will take the sum of the numbers in each row and ...
8
votes
1answer
730 views

13-by-13 SIKAKU puzzle

A SIKAKU puzzle consists of a square or rectangular grid in which some of the cells contain a one or two digit number. To complete the puzzle, a Solver must divide the puzzle into a number of ...
11
votes
1answer
1k views

Futoshiki Puzzle with the least amount of clue

You are supposed to create a new $5$x$5$ Futoshiki puzzle with the least amount of clues possible, but this puzzle needs a unique answer. In other words, What is the minimum number of clues for $5$...
4
votes
2answers
200 views

Modified Futoshiki

This is a modified Futoshiki Place the numbers 1 to 5 such that each row, and column contains each of the digits 1 to 5. Squares with same color, contains each of the digits 1 to 5 too.
7
votes
1answer
336 views

Slitherlink - It's all in the 2s

Can you solve this Slitherlink puzzle that I came up with? And in CSV: 3 - 3 - 2 - - 2 - 2 - 2 - - 1 1 2 2 1 - - 2 - 2 2 - - - 2 - 1 2 - - 1 - I tried to ...
3
votes
2answers
400 views

Another Determinant Sudoku

sudoku-determinant have been described well here : The Determinant Sudoku I have created another one. Number in the center is the value of the determinant Numbers 0 to 10 are the values of the ...
13
votes
2answers
533 views

A spiral Ripple Effect puzzle

I'd say the rules to a ripple effect puzzle are best explained here. Anyways, I was making a bunch of Ripple Effects and decided to do a big one which didn't work out as I'd hoped, in that I needed ...
4
votes
2answers
195 views

Bullet Drop™ #1

Concept Here is a basic example grid: AB 1\/ 2\/ ×× The player must first modify the grid by switching the slashes \ and <...
8
votes
3answers
607 views

Getting all same side pairs

The goal is to get same side pairs of the 6 tiles, , to fit into a $2\times 3$ grid, so that all touching sides match like so (excluding the red part), for example:
0
votes
1answer
230 views

The Gardener's Route

Tell me the method for solving such grid problems in detail. I need a solution for The Gardener's problem.Tell me any method to construct the grid.
3
votes
1answer
118 views

Fill up the grid with the letters 'P', 'U', and 'Z' in the following way

Fill up the grid, , so that the letters '$P$', '$U$', and '$Z$' occur the same number of times both column-wise and row-wise, as well as diagonally for all diagonals with a number of cells that is a ...
14
votes
1answer
507 views

Why you shouldn't buy cheap puzzle books

Backstory contains important information, but nothing hidden. Also, tl;dr parts are bolded, but I can't guarantee I didn't forget bolding some part. Recently there's been a grid-deduction craze here ...
14
votes
5answers
983 views

A problem about Yin-Yang puzzles

In a Yin-Yang puzzle, one must fill every cell with either a black circle or a white circle according to the following rules: All cells with black circles form an edge-connected region. All cells ...
8
votes
1answer
183 views

4 More Meander Puzzles

My previous set of meander puzzles was fairly well-received, so I decided to make some more. If you didn't see the first set of meander puzzles, the instructions can be found here. Here they are: ...
27
votes
1answer
817 views

Every Fourth Wormhole

An entry in Fortnightly Topic Challenge #33: Surface Geometry Mazes
76
votes
2answers
3k views

My God, it's full of stars!

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids My dear friend, unknown to us, may have relocated again. He sent me imagery and constellation maps indicating that a distant red ...
8
votes
1answer
274 views

Puzzles: Meander

I have come up with an interesting type of puzzle based on the mathematical concept of a meander. The concept, of course, is not original to me, but the type of puzzle is, as far as I know. A ...
15
votes
2answers
659 views

Tetromino Sudoku

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids The grid below, when filled in, forms a valid Sudoku grid. It can also be filled in like a LITS (nuruomino) puzzle without the 1x4 ...
41
votes
2answers
2k views

I am an island (ysaujdiolkiun)

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids I received an envelope containing two drawings and no return address. I would recognize that handwriting anywhere - my dear friend ...
27
votes
3answers
967 views

Oh no, it's another safe!

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids Oh, did I feel proud after solving the last safe... until I was immediately dimension-doored (or something) into this room! Damn ...
51
votes
1answer
2k views

The Ludicrous Loop: over a thousand cells of circular logic!

Flavourtext is for flavour only. Ladies and Gentlemen, are you feeling ludicrous today? A little loopy, perhaps? Then come one, come all, for I have just the thing for you. Lampreys and Jellyfish, ...
52
votes
4answers
2k views

Desert Irrigation Project

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids My dear friend researches and designs canal irrigation systems in a remote desert. He's been missing for two weeks. Members of ...
30
votes
2answers
2k views

Parallelisation

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids Puzzlers, I am presenting a set of six duo-grids! Of course, I need to tell you how they work - you are given a grid. Looking at it,...
18
votes
2answers
601 views

Introducing: Jormungand

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids Introducing: Jormungand A combination of Ouroboros (Slitherlink) and Numbersnake (Numbrix) to create the greatest snake-themed ...
18
votes
1answer
770 views

A Knight's Kuromasu

An entry in Fortnightly Topic Challenge #32: Grid Deduction Hybrids You are a knight in the king's army, and you've been tasked with constructing some walls. The problem is, as a knight, you are ...
2
votes
1answer
667 views

Move 2 or 3 spaces in this 5 by 5 grid

You have a 5 by 5 Board as shown. You start from the S (Center) position. You can: 1 Move TWO or THREE spaces only 2 You can move Vertically or Horizontally or Diagonally but only in a straight ...
2
votes
1answer
181 views

Arrangement at the puzzling class

PSE open a puzzling class. 16 students join the class. the classroom have 16 chairs arranged in (4 x 4) grid. ...
30
votes
3answers
3k views

Messages hidden in the “visit every square once” puzzle

I proposed my girlfriend yesterday, asking her to be my wife. but she did not answer me. Besides she gave me this 6 puzzles, below. She said I will know her answer after solving the puzzles. Inside ...
13
votes
1answer
524 views

Hexagonal Kurokuron

Kurokuron (クロクロ一ン: "black clone"), is a shading puzzle that first appeared in Puzzle Communication Nikoli issues 153-155. Identical rules apply to a hexagonal grid. Rules Shade some cells such that: ...
8
votes
2answers
1k views

Fill this 5x5 number grid incrementally, either by moving two boxes diagonally or moving three boxes in a row or column

One day, a friend has shown me a 5 by 5 grid, challenging me to fill it with numbers from 1 to 25. Obviously, it is not simple because there are some rules: The number 1 is placed in the center of ...
11
votes
1answer
2k views

Nested sudoku in entrance exam

My university set this question in 2013's entrance exam. Also the red boxes include from 1 to 9. What's the solution for this sudoku?
4
votes
1answer
767 views

Can you solve this kakuro puzzle?

This kakuro puzzle comes from the newest edition of Topple, an indie puzzle magazine I run. For those who are unfamiliar with kakuro, here are some instructions: Kakuro consists of a blank grid with ...
32
votes
3answers
3k views

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 ...