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. Use with the [logical-deduction] tag. 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.
982
questions
12
votes
1
answer
530
views
PSE Advent Calendar 2021 (Day 17): That's the way the cookie crumbles
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 >
In our house,...
- 26.3k
17
votes
2
answers
672
views
PSE Advent Calendar 2021 (Day 15): Optics Experiment
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 >
Optics ...
- 680
9
votes
2
answers
522
views
Christmas tree LITSO
Inspired by PSE Advent Calendar 2021 (Day 13): A Christmas Hokuro, I challenged myself to create a Christmas tree-shaped puzzle. Unfortunately I had to edit the shape a little bit because... reasons. ...
- 11.6k
15
votes
1
answer
735
views
PSE Advent Calendar 2021 (Day 13): A Christmas Hokuro
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 >
Hokuro is a ...
- 5,208
8
votes
3
answers
317
views
Place digits from 1 to 7 into each row and each column of the grid once. Numbers in the circles give the product of the four surrounding digits
What is the way to resolve the following puzzle?
Link to source. It's from a taiwanese math olympiad held in 2005.
- 81
14
votes
2
answers
836
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 >
"...
- 26.3k
15
votes
2
answers
836
views
PSE Advent Calendar 2021 (Day 3): Tentai Show
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 >
Divide the ...
- 76.5k
5
votes
1
answer
280
views
10x10 Fillomino
Interactive solving website
For help/rules on solving, please look at the website's "help" section, which lists fillomino rules. Please use the website to solve the puzzle unless you are ...
user77687
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 ...
- 7,434
4
votes
1
answer
825
views
Am I able to mark mines with the bottom row of 3's?
Am I able to use the bottom row of 3's to know what some of the squares around it are?
- 181
4
votes
2
answers
480
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 ...
5
votes
3
answers
2k
views
Is there anywhere else I can go without guessing randomly?
I’ve been looking at this board for a little while, and can’t seem to find any places to go where I don’t have to guess. Is guessing the only thing I can do here, or are there strategies that I’m ...
- 181
1
vote
1
answer
178
views
How do I know where the bombs are?
I’m not sure how I would know, because in the top right corner, where there is a 2, 3, 2, going down, the bottom two needs to touch two mines and so does the top. But if I did the immediate right ...
- 181
0
votes
1
answer
134
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.
0
votes
1
answer
172
views
How could I have known not to go here?
How could I have known not to press where the red bomb is?
- 181
0
votes
2
answers
107
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.
2
votes
2
answers
314
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 ...
22
votes
1
answer
1k
views
The Tree is Growing
I just found this new type of puzzle and I think the rule set is fun! So, I decided to create one.
Rules (taken from the original puzzle):
Create non-intersecting non-looping trees such that the ...
- 918
1
vote
1
answer
370
views
Find the hidden message in... this grid
(So I made this puzzle, and I wanted it to be fun rather than difficult! I hope it’s original enough)
Given a 5x5 grid as input, here’s an algorithm:
randomly select any 3x3 grid within the 5x5 grid
...
- 21
2
votes
1
answer
687
views
Can you check the results of this chess match?
As the sun broke the horizon I could feel the cold breeze on my face mixing with the warming city air. Like most mornings, I could hear Mr. and Mrs. Shamming discussing their afternoon plans during ...
- 10.6k
16
votes
1
answer
782
views
Ripple Effect ... with Inequality Sign
I was making ripple effect but failed on uniqueness. That leads me to think of using inequality signs to fix the puzzle. Then, I'm wondering, what if, I make a new one with intentional inequality ...
- 918
3
votes
1
answer
219
views
Cube Connect Challenges
Cube Connect is a Flow-like mobile puzzle game on the surface of a cube.
Rules of Flow (which is simply Numberlink with colors instead of numbers; copied from Nikoli rules with small modification):
...
- 11.6k
8
votes
1
answer
307
views
Themed Boggle Grids
Inspired by this puzzle, I created (or discovered) these grids.
Within each Boggle board is a set of words with a common theme.
To make a word in Boggle, connect some letters horizontally, vertically, ...
- 2,699
9
votes
1
answer
360
views
Double Choco: I love myself
Rules of Double Choco: (copied from here)
Divide the grid into regions by drawing along some of the dotted lines.
Each region should have one group of gray cells and one group of white cells; both of ...
- 11.6k
13
votes
1
answer
558
views
Pipelink: A Cat for jkittykitkat
Rules of Pipelink:
Draw a loop through the centers of all cells.
Two perpendicular line segments may intersect (cross) each other, but not turn at their intersection or otherwise overlap.
Clues show ...
- 34k
5
votes
3
answers
363
views
Filling a grid with skinny trominoes which have arrows on their ends
Let's have a 10x10 square grid with 7 empty small squares. This grid is to be filled with skinny
trominoes which have arrows at their ends (see figure 1). What is the maximum number of arrows
which ...
- 2,917
15
votes
2
answers
918
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 ...
- 34k
6
votes
4
answers
1k
views
Train Tracks: is there a unique solution?
In the last year or so a puzzle has been appearing in 'The Guardian' (a UK newspaper). It looks like this:
and the instructions are as follows:
Lay tracks to enable the train to travel from village ...
- 183
17
votes
3
answers
624
views
Oh no, my puzzles are corrupted! What should I do? :(
This morning, I made three small and easy puzzles to be posted today. However, when I come back from my lunch, all of my puzzles are corrupted! :(
The first one is a standard Curve Data puzzle. ...
- 34k
3
votes
2
answers
325
views
It's kind-of like Minesweeper
Have you ever played "Minesweeper" or "Lights Out!" and wondered what it would be like to reverse the process? Me too! Say hello to a 10 by 10 grid that I like to call "Number ...
- 10.6k
4
votes
1
answer
758
views
6
votes
3
answers
466
views
Spin the letter-squares!
Spin the letter-squares!
A 5x3 grid of letters, e.g.,
a b c d e
f g h i j
k l m n o
can be rearranged by spinning either the 3x3 section centered at the second letter of the second row (in this case ...
- 711
3
votes
1
answer
204
views
Let's settle our differences
Can you complete this grid and expose the existing relationships? There are no complex operations (e.g. no exponents, square roots, functions, etc), additionally the numbers are all natural numbers ...
- 10.6k
3
votes
2
answers
397
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 &...
- 31
8
votes
1
answer
669
views
Can you reactivate a 4x4 Magic Square?
We've already removed the magic from a 3x3 magic square. Recently, one of our 4x4 magic squares was scrambled in an earthquake and I need your help to reactivate it's magic:
Objective
Your objective ...
- 10.6k
3
votes
2
answers
510
views
Fix this puzzle, please!
My students claim that this disconnect four puzzle (fill the grid with crosses and zeros, such that no four equal symbols appear in a row. Rows can be horizontal, vertical, or diagonal) does not have ...
- 16.9k
6
votes
3
answers
915
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 ...
- 163
9
votes
2
answers
419
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 ...
- 33.1k
12
votes
1
answer
298
views
KPK 2021 Leftover: Double Back (Little Killer)
Rules of Double Back:
Draw a non-intersecting loop through the centers of all empty cells.
The loop passes through each region exactly twice.
These two puzzles are the leftover of KPK 2021.
The ...
- 34k
13
votes
2
answers
955
views
Remove the magic from a 3x3 Magic Square
It's commonly stated that there is only one solution to the 3x3 magic square. This is simply because every variant found is simply a rotation, reflection or both of any other variant. Once such ...
- 10.6k
8
votes
1
answer
158
views
Trichain: Tetrachain
This is a Trichain puzzle. The rules of Trichain are as follows:
Numbers must be white, and match the size of their white islands.
Each white island can only contain at most one number. Some white ...
- 10.4k
3
votes
1
answer
220
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 ...
- 821
11
votes
2
answers
579
views
Confectionery Crime Conundrum
Yesterday I received one of the strangest cases of my career as an I.S. PI (Insightful Sleuths Private Investigator). I was reclining in my chair, working on the latest crossword puzzle when I ...
- 10.4k
11
votes
1
answer
240
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 ...
- 6,996
0
votes
1
answer
176
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 ...
- 219
20
votes
1
answer
1k
views
Tapata (Tapa variation)
Rules:
Shade some cells so that all shaded cell form one orthogonally connected area.
Numbered cells are either tapa clue (represent the lengths of the shaded cell surrounding that clue) or pata clue ...
- 918
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 ...
- 56.4k
10
votes
2
answers
2k
views
Strategies for Circuit Board Puzzle from NYT
The New York Times publishes a collection of variety puzzles each week, and new to the rotation recently is one called "Circuit Board". Here is an example of a puzzle (I added coordinates ...
- 277
3
votes
1
answer
224
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 ...
- 821
2
votes
1
answer
304
views
Mysterious Deaths, or is it just a well known attack?
Last week you were promoted to the position of Sergeant Head Detective of Australia, which basically means the best detective in Australia. Its January 2019, and you wake up ready for your new job.
...
- 2,559