Sudoku embedded in a Kakuro


In addition to standard Kakuro rules, the grey shaded cells must form a valid Sudoku solution

The puzzle below has been corrected.  See here for a highlight of the correction.


The puzzle can be found in this printable PDF, or in the image below.

PDF Embedded Sudoku Kakuro

Embedded Sudoku Kakuro 1-01

Killer Sudoku Hybrids

Over these last few weeks I’ve returned to my roots with a few Killer Sudoku variants, which I recently posted to the Daily League on Facebook.  I have a few more ideas, but they’ll have to wait until after finals.

Star Battle Killer

Place the numbers 1-8 and two stars in each row, column, and jigsaw group. Stars cannot touch each other, even diagonally. Numbers cannot repeat within cages. Stars count as 0 in cages.


Butterfly X Nurikabe Killer

This puzzle is made up of four overlapping 9×9 Sudoku grids arranged in a butterfly pattern (1 in each corner), each with it’s own set of main diagonals, which must contain the numbers 1-9.  The sum/size of all cages are given, but not their shapes.  The shapes of cages must form islands in a valid Nurikabe solution.  Givens are shaded, and thus cannot be part of a cage.


Killer Battleships

Classic Sudoku rules apply.  Additionally, a fleet of battleships must be placed into the grid, such that they do not touch, even diagonally.  Cells occupied by the battleships must add up to the sum associated with each ship, and any cell sharing an edge with a ship cannot contain any of the numbers inside the ship.  Numbers on the outside of the grid indicate how many cells in that row or column are occupied by a ship.  Givens are “sea” squares, and cannot contain a ship.


Trapezoids Compound

I’m happy to announce my first e-book release on this blog!  I borrowed an idea from David Millar, whose Area 51 puzzles combine clues from Slitherlink, Fences, Cave, and Masyu.  I wanted to see how far I could take this idea, layering as many types of clues as I could into one of my own puzzles.

This collection of 20 puzzles introduces 8 different types of clues and explores how they interact with each other.  Most of these puzzles are Hard to Expert difficulty, so expect a challenge.  If you would like some easier puzzles to start out on, check out the original Trapezoids post from June.

Here is the e-book in pdf form laid out and formatted to letter size:

PDF Trapezoids Compound e-book

The content of the e-book in blog form follows, except the solutions.

Round 1 – Base Rules

Standard Trapezoids rules:

Shade some cells such that numbers indicate exactly how many surrounding cells are shaded.  Shaded cells must be in edge-connected clusters of 3, forming trapezoids.  A trapezoid may not share an edge with another trapezoid. All remaining unshaded cells are connected edge-to-edge.




Round 2 – Simple Givens

Some shaded cells are given.




Round 3 – Unshaded Givens

Cells with single or double circles must be unshaded, and thus must be connected to the remaining unshaded cells.  Cells with a single circle must be touching exactly one shaded cell.  Cells with a double circle must be touching exactly two shaded cells.




Round 4 – Row Counts

Numbers on the outside edge of the grid indicate the total number of shaded cells in the indicated row.  Only shaded cells, including givens, are counted.




Round 5 – XOR Dots

Dots on the border between two cells indicate that one cell is shaded and the other is not.




Round 6 – XY Givens

Some shaded cells are given, marked with an X or Y.  EITHER all of the cells with an X have one neighboring shaded cell and all of the cells with a Y have two neighboring shaded cells OR all of the cells with an X have two neighboring shaded cells and all of the cells with a Y have one neighboring shaded cell.




Round 7 – Interior Borders

Trapezoids cannot cross interior borders.  The interior borders create regions, each of which must have at least one shaded cell.  Interior borders do not block unshaded cells from connecting.




Round 8 – Obstructions

Large black dots inside of a cell represent obstructions, which block unshaded cells from being connected.    Additionally, obstructions cannot “see” each other; in any row of cells in which there is more than one obstruction, at least one of the cells between them must be shaded.  Just like in row counts, a row of cells is either 0° (horizontal), 60° or 120°. Obstructions must be connected to the mass of unshaded cells.  Obstructions are not counted in row counts.