All Questions
Tagged with grid-deduction no-computers
70 questions
5
votes
1
answer
320
views
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 ...
- 2,809
1
vote
1
answer
106
views
Shikaku grid deduction puzzle
Japanese publisher Nikoli produces this geometric logic puzzle. Can you divide this grid into rectangular and square pieces such that each piece contains exactly one number and each number reflects ...
- 5,231
14
votes
1
answer
672
views
Double Grid Miracle Sudoku
A miracle sudoku is a name of a sudoku given with what looks to be so minimal information that it at first seems impossible to work, first started and mentioned in this video by Cracking the Cryptic. ...
- 2,967
5
votes
1
answer
193
views
Current record for minimally clued 7x7 Hidato (16 clues)
Background
Back in March, I posted this question on the Puzzling Stack Exchange asking how many clues were needed to create a 4x4 Hidato puzzle with a unique solution.
Sometime after this, I took a ...
- 2,809
6
votes
1
answer
628
views
Oh no, my chocolate banana puzzles are not unique!
There is a hidden message (7, 2) inside the solutions of the nine puzzles. An answer will only be accepted if it correctly identifies said message.
Here are the Chocolate Banana puzzle rules. Each ...
- 3,223
6
votes
2
answers
909
views
Create an empty 8x8 One Up puzzle with a unique solution
Rodolfo Kurchan created a wonderful new grid puzzle called One Up that you can play on his website. There is one main rule:
Each horizontal and vertical sequence of N cells between walls, must contain ...
- 37.6k
3
votes
1
answer
181
views
Themed 7x21 Chocona
Chocona rules differ from Chocolate Banana rules.
There is a hidden message inside the solution of the puzzle. An answer will only be accepted if it correctly identifies said message. The message is ...
- 3,223
5
votes
1
answer
222
views
Themed 13x9 Chocolate Banana
There is a hidden message inside the solution of the puzzle. An answer will only be accepted if it correctly identifies said message.
P.S. I promise this is my last Chocolate Banana puzzle of the ...
- 3,223
11
votes
2
answers
532
views
Prime and Composite 6x6 Chocolate Banana
The number of chocolates (black regions) is prime.
Normal Chocolate Banana rules apply.
Rules:
Paint some of the cells black.
Black cells linked orthogonally must always form a rectangle (or a ...
- 3,223
9
votes
1
answer
291
views
9x13 Chocolate Banana Puzzle $\pi=\frac{43}{3.7^2}$
Since 37 is my favorite integer and π is my favorite number, here's another puzzle:
Normal Chocolate Banana rules apply.
Rules:
Paint some of the cells black.
Black cells linked orthogonally must ...
- 3,223
7
votes
1
answer
290
views
11x13 Chocolate Banana Followup
Your goal is to maximize the absolute difference of the numbers marked ?.
(? marks indicate region areas. They may or may not ...
- 3,223
14
votes
1
answer
1k
views
10x10 Choco Banana
Normal Chocolate Banana rules apply.
Rules
Paint some of the cells black.
Black cells linked orthogonally must always form a rectangle (or a square).
Non-blacked cells linked orthogonally must not ...
- 3,223
3
votes
1
answer
252
views
Minimally clued 4x5 Hidato (4 clues)
Puzzle attribution: Me :)
Background
So as you might or might not know, I have been studying the minimum number of clues needed to force a unique solution in Hidato for variously sized boards. I ...
- 2,809
23
votes
1
answer
917
views
Invalid Jigsaw Sudoku Layout
The Jigsaw Sudoku Layout below is invalid (no Latin Squares exist for it). Why?
Please find a short, yet complete, explanation (no computations involved).
...
- 470
9
votes
1
answer
616
views
Hardcore Lighting - Excalidraw
Each yellow cell is a light that shines in exactly one direction, horizontally, vertically, or diagonally, endlessly, and goes through any block as long as the block is not a wall. Black cells do not ...
- 3,223
11
votes
1
answer
496
views
Best Wishes for 2024: Four empty Suguru (Tectonic) puzzles
To continue last year's tradition, hereby four empty suguru puzzles.
Rules of suguru: Each square gets a number so that each block of n squares has the numbers 1..n, and neighbouring squares (...
- 1,445
18
votes
2
answers
811
views
PSE Advent Calendar 2023 (Day 9): The Peppermint Twist
This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2023. The accepted answer to this question will be awarded a bounty worth 50 reputation.< Previous Door Next Door >
This puzzle ...
- 29.2k
1
vote
1
answer
161
views
A Hidato, but with no given numbers?
I can be a bit evil sometimes. Today, I am going to give you a Hidato with no numbers! It gets worse: This puzzle is on a Mobius Strip Y[1] However, I will give hints as to what the numbers are, so ...
- 2,809
11
votes
1
answer
797
views
A Hidato, but with a complex twist!
Today's Hidato puzzle has a pretty complex twist. What is the twist, you ask?
This is what the twist is:
There are three different colors:
Yellow: Represents a prime number
Green: Represents a ...
- 2,809
15
votes
1
answer
1k
views
Trust me: you do not want to go down this road with me
Every cell has a digit from 0 to 9 or one of the four operation symbols +, −, ×, and /, signifying addition, subtraction, multiplication, and division respectively.
No digit appears more than once in ...
- 13.3k
28
votes
2
answers
2k
views
A logician's Bingo
Mark some cells on the following Bingo board, so that all statements in marked cells are true AND all statements in unmarked cells are false.
A Bingo here is a set of five marked cells in a row, ...
- 17.1k
9
votes
3
answers
2k
views
The Universe's Secret
To find the universe's secret, first solve the Sudoku variant with #s 1-7 only.
No number may be repeated on any diagonal. No numbers go in the squares with red or green dots.
Then use the solution ...
- 19.3k
5
votes
2
answers
430
views
a six-by-six KenKen
The rules of KenKen are as follows:
You must fill in the numbers 1 through 6, one number per box, in the grid, so each row and each column contains each number exactly once.
Each heavily outlined ...
- 13.3k
12
votes
1
answer
559
views
A massive synonym
Please explain how to assemble the puzzle.
Yes, one is missing, but you can follow the >.
No computers.
Hint:
Hint 2:
Hint 3:
Text version:
...
- 30.2k
7
votes
1
answer
1k
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, ...
- 81
30
votes
1
answer
891
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 ...
- 29.2k
14
votes
2
answers
899
views
PSE Advent Calendar 2021 (Day 4): Decorating with Ingrid Deduction
This puzzle is part of the Puzzling StackExchange Advent Calendar 2021. The accepted answer to this question will be awarded a bounty worth 50 reputation. < Previous Door Next Door >
"...
- 29.2k
11
votes
1
answer
247
views
Tiling three pears with three-pair hexominos
The 21 hexominos below are all those that can be made by joining three dominos together (i.e. they have a perfect matching with respect to the graph of their squares) and are not rectangles. The ...
- 8,805
3
votes
1
answer
314
views
Quadruped Mosaic
This is a visual puzzle (known as "mosaic" or "fill-a-pix") with the same rules as MineSweeper:
This puzzle has exactly 100 x 100 cells.
The grid is to be filled with colored and ...
- 766
7
votes
1
answer
336
views
A 3x3 grid with common factors
A $3 \times 3$ grid $G$ is filled with every number from the set $\{2,3,5,6,7,11,14,15,30\}$. Now a new $3 \times 3$ grid $H$ is formed, such that $H_{ij}$ is the number of neighbors of $G_{ij}$ that ...
- 37.6k
10
votes
4
answers
1k
views
Deriving a 3x3 grid from another one
A $3 \times 3$ grid $G$ is filled with every number from $1$ to $9$. Now a new $3 \times 3$ grid $H$ is formed, such that $H_{ij}$ is the number of neighbors of $G_{ij}$ that are greater than $G_{ij}$....
- 37.6k
21
votes
1
answer
881
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 ...
- 29.2k
9
votes
1
answer
458
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 ...
- 5,162
3
votes
1
answer
358
views
Will forcing chains break this sudoku puzzle?
I am trying to pick up advanced sudoku techniques by practicing with “difficult” puzzles as suggested by my sudoku app.
In this puzzle, I am stuck in the position as shown below. I think I can make ...
- 133
26
votes
2
answers
4k
views
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 ...
- 64.9k
68
votes
2
answers
5k
views
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. ...
- 64.9k
5
votes
2
answers
594
views
Multiplicative sudoku (don’t use computers please)
If I place all the numbers from 1 to 9 in a 3x3 grid and I add the products of each row and column, then what is the minimal and the maximal sum?
For example, the sum is 450 on the picture above
- 51
7
votes
2
answers
305
views
Another follow the path of relation through the grid
Inspired by Galen's series of puzzles...there is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-...
- 29.2k
4
votes
1
answer
151
views
Follow the path of relation through the grid #9
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
3
votes
1
answer
161
views
Follow the path of relation through the grid #8
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
4
votes
1
answer
218
views
Follow the path of relation through the grid #7
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
5
votes
1
answer
157
views
Follow the path of relation through the grid #6
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
5
votes
2
answers
239
views
Follow the path of relation through the grid #5
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
3
votes
1
answer
172
views
Follow the path of relation through the grid #4
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
6
votes
1
answer
230
views
Follow the path of relation through the grid #3
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
7
votes
1
answer
282
views
Follow the path of relation through the grid #2
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
12
votes
1
answer
374
views
Follow the path of relation through the grid #1
There is a relation between rectilinear-adjacent squares such that there is a unique rectilinear path from the top-left corner of the grid down to the bottom-right corner of the grid. Each square can ...
- 2,296
10
votes
3
answers
848
views
Cipher text on an ancient wall
The following text was found written on the wall of an ancient tomb:
$\text{DXFDMKEPU}$
Can you decipher what it means?
Nearby the wall, this piece of parchment was found. Perhaps it is a clue ...
- 10.5k
8
votes
2
answers
249
views
What Goes Round (Begriddled logic puzzle)
Join adjacent numbers in the below grid to reveal the hidden content.
The rules are:
1: Join all pairs of vertically and horizontally adjacent numbers that are the same.
2: Join all pairs of ...
- 353
4
votes
1
answer
254
views
Humans, vampires and mirrors part 2: the triangular mirrors
Find part 1 (without triangular mirrors) here.
Here is a room composed of $10 \times 10$ squared cells. Each cell can be empty (𝑋) or contain one of the following:
a double-faced mirror ( / or \ );
...
- 5,162