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.

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2
votes
2answers
109 views

Mario's Super Picross - Stage Mario 9-K

I'm playing through Mario's Super Picross currently and after nearly 200 puzzles this one finally has me stumped as to how it is intended to be solved. What is the next step to solving this? Notes: ...
-3
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0answers
138 views

Reverse Sudoku (irregular version)

Here is a complete 11x11 irregular sudoku page. Remove numbers from the boxes until you have 10 numbers left, then see if the puzzle can be solved (in normal sudoku) again. All of the numbers along ...
14
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1answer
318 views

Cartological Cats: A Snaky-Loop Grid Puzzle with Cat-Shaped Matchmaking Clues

This is written for calica for a Secret Santa puzzle exchange. The original version in a printable PDF format can be found here. Dear calica, Thank you so much for being an amazing person this year! ...
0
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1answer
88 views

Is X-Sudoku easier to solve than classic Sudoku [closed]

X-Sudoku has extra rule for diagonals which give extra hints for diagonal cells. Does this implies that solving X-Sudoku puzzles are easier than classic Sudoku puzzles?
4
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3answers
869 views

Finding a Kakuro trick

The following screenshot is taken from the Android app Kakuro++ (level 9 riddle 12) And I verified the current status within the app. I managed to solve the puzzle by guessing a 50/50-number and ...
10
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1answer
209 views

Snowcaps - A grid deduction puzzle

This winter-themed puzzle is basically an upside-down Aquarium, the idea being that instead of fish tanks being filled with water, the areas are mountains being covered with snow. The goal is to shade ...
20
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1answer
460 views

PSE Advent Calendar 2021 (Day 24): The Witneys - Your Comfy Puzzles

This puzzle is part of the Puzzling StackExchange Advent Calendar 2021. The accepted answer to this question will be awarded a bounty worth 200 reputation.< Previous Door Your great-grandmother ...
28
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1answer
623 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 ...
11
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1answer
471 views

PSE Advent Calendar 2021 (Day 19): Santa's Dilemma

This puzzle is part of the Puzzling Stack Exchange Advent Calendar 2021. The accepted answer to this question will be awarded a bounty worth 100 reputation.< Previous Door Next Door > It was ...
12
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1answer
421 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,...
16
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2answers
533 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 ...
9
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2answers
457 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. ...
15
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1answer
568 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 ...
7
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3answers
181 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.
13
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2answers
591 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 > "...
15
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2answers
688 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 ...
5
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1answer
239 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 ...
16
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2answers
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 ...
4
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1answer
780 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?
4
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2answers
454 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 ...
6
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3answers
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 ...
1
vote
1answer
146 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 ...
0
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1answer
112 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
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1answer
135 views

How could I have known not to go here?

How could I have known not to press where the red bomb is?
0
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2answers
100 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
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2answers
285 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
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1answer
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 ...
1
vote
1answer
169 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 ...
2
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1answer
665 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 ...
15
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1answer
722 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 ...
3
votes
1answer
135 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): ...
9
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1answer
233 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, ...
9
votes
1answer
269 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 ...
13
votes
1answer
490 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 ...
4
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3answers
331 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 ...
15
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2answers
841 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 ...
6
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4answers
771 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 ...
17
votes
3answers
514 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. ...
3
votes
2answers
279 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 ...
4
votes
1answer
720 views

A 4x4 grid of red?

How is this 4x4 grid of red, colored? The only hint I'll give is that
6
votes
3answers
441 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 ...
3
votes
1answer
193 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 ...
3
votes
2answers
344 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 &...
8
votes
1answer
459 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 ...
3
votes
2answers
281 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 ...
6
votes
3answers
877 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 ...
9
votes
2answers
222 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 ...
12
votes
1answer
274 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 ...
12
votes
2answers
809 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 ...
8
votes
1answer
137 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 ...

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