# 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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### Who can spot the difference?

My family and I have just moved house! Lucky us! So what did my family do? We held a housewarming party, and rung everyone in the neighbourhood up to invite them. So, anyway, people were coming in ...
1k views

### Three for the price of one

While browsing through your local puzzle store, you see something you can't resist: a box which promises two grid deduction puzzles for the price of one! The vendor explains that the box contains a ...
855 views

### A Total Masyu puzzle

In a Total Masyu puzzle, one must draw a single loop through the centres of some cells according to the following rules: The loop may only travel horizontally or vertically, never diagonally; all ...
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 ...
1k views

### Hexagonal Grid Filling

Fill in each blank white hexagon with a digit from 1 to 9. Each of the grey hexagons is the sum of the white hexagons around it, and all of the white hexagons that are around the same grey hexagon ...
952 views

### A letter from Mr. Pirate, Mr. Roller, and Mr. Knight

Though I don't think it will help, you may check with the beginning of my story concerning Red Herring Puzzle Club. It seems like it's been a long time since I tried to enter the R.H.P.C. As you may ...
1k views

### Sudoku with only 8 predefined numbers

Have fun with my self-made Sudoku puzzle. Solve this Sudoku puzzle using the standard Sudoku rules: Fill any row, column and bold-framed area with the numbers 1 to 9. Hint: It is not as difficult as ...
483 views

### Introducing Tetronogram - Beginner's Version

Introducing Tetronogram! (named by @MrPie) The puzzle is made of a grid like a nonogram. Notations are along the axes like a classic nonogram but numbers are replaced by the names of the ...
685 views

### Time to Hit the Bricks!

An entry in Fortnightly Topic Challenge #24: Grid-Deduction... It's 2am. The phone rings. You answer it and are immediately met with an onslaught of franticness from your (in?)famous uncle—a ...
381 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 ...
319 views

### Diabolical Deceptions: A 333rd Birthday Tribute to J.S. Bach

Johann Sebastian Bach is one of the most famous composers from the Baroque period. If he was still alive today, he’d be 333 years old. So, let’s celebrate 3 of his most famous works with a 33x33 loop ...
498 views

### Statue Park: Knight's Lines

This is a Statue Park puzzle. Rules of Statue Park: Shade some cells of the grid to form the given set of pieces. Pieces may be rotated or reflected. Pieces cannot be orthogonally adjacent (though ...
2k views

### This puzzle design was a DISASTER!

As any member of the PSE community knows, grid-deduction puzzles really aren't my forte. In fact, I'd like to share one particularly disasterous attempt at designing a Slitherlink puzzle. Disclaimer:...
774 views

### HAISU: Nought and Crosses

HAISU is a portmanteau of three Japanese words - 'hairu', to enter, 'su', number, and 'hausu', an English borrow word meaning house, of course. Together, we get a meaning of 'enter number house', ...
458 views

### Tiling a square with rectangles

Tile completely this 47 x 47 square with 52 rectangles. Each rectangle must contain precisely one numbered cell, and that number must be the area or perimeter of the rectangle it finds itself in. ...
577 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 ...
422 views

### Karst - A variant of Cave

This is a variant of Cave applied to a 3.4.6.4; 3.42 6; 44 tiling. Rules Draw a single loop along the dashed lines that encloses some cells. Edges of this loop may not cross or share a ...
349 views

### Statue Park: Apollo 11

This is a Statue Park puzzle, made in honor of the 50th anniversary of the Apollo 11 mission. Rules of Statue Park: Shade some cells of the grid to form the given set of pieces. Pieces may be ...
2k views

### Virus Detected - Please execute anti-virus code

Virus Detected!!! Your computer, which is represented by the grid pictured, has been infected. The bugs are clearly marked. It's your job to inject your awesome anti-virus code in the proper computer ...
345 views

### Oriental HAISU - An unoriginal grid-deduction challenge

TheGreatEscaper comes up with several inventive (and original) grid-deduction genres, so I thought I'd try my hand at combining two of them. HAISU The rules are simple - draw a path from the O to ...
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 ...
506 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 ...
1k views

### Sum in A Sudoku

Color Blind version: Here's a sudoku puzzle with a twist! The numbers given in the squares are actually the sum of the numbers in that region. For example: 18= Sum of the numbers in the 4 yellow ...
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 ...
549 views

### Mini Ripple Effect puzzles

I enjoyed this puzzle so much that I created some mini versions of it for fun. I signed up to share them with everyone. The rules are the same: Each region with n cells contains all the numbers from 1 ...
645 views

### 3D Masyu - A Die

Fold this net into a cube and solve this 3D Masyu. The original Masyu rules apply. In addition, question mark '?' should be replaced by either a black or white circle. Side note: Yeah, it's almost ...
324 views

### Heyawacky: Ace of Cups

This is a Heyawacky puzzle. The rules are the same as Heyawake, but non-rectangular regions are allowed. Rules of Heyawake: Shade some cells of the grid. Shaded cells cannot be orthogonally ...
805 views

### (1 of 11: Numberlink) What is Pyramid Cult's Favorite Activity?

Dear PSE users and moderators, I’m new here in PSE, but I really need your help. There was this person who gave me a black envelope consisting 10+1 pages of puzzles, and also a scribble saying: “Find ...
982 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 ...
491 views

Rules: Hey, this looks like slitherlink! In fact, it is two slitherlinks added together. So both of the two slitherlinks have clues in exactly the same locations as this grid below. Furthermore, a 2 ...
638 views

### A Trip to Ripple Islands

All aboard! All aboard! You have won an ALL-EXPENSES PAID TRIP to the magnificent Ripple Islands! Now, the only price of admission is to solve this little puzzle. It is a Ripple Effect puzzle based ...
876 views

### 3D nonogram – Name the object

This is a 3D nonogram. The first five boxes represent the five layers of a $5\times5\times5$ cube, and the last box shows the enumerations for the Z-axis. (Note that 11 means two stretches of length ...
942 views