Erasable Games Weblog

(Sudoku in words and pictures)

Archive for May, 2007

Sudoku To Kakuro

Sunday, May 27th, 2007

Sudoku  To  Kakuro

I’ve been doing Cross-Sum puzzles for many years, but now that it’s called Kakuro (abbreviation of Japanese kasan kurosu: addition cross), it seems somehow new. Certainly the Puzzle book publishers think so. Where there was previously only a section in a crossword puzzle book there is now entire puzzle books devoted to Kakuro.

In solving these kinds of puzzles it may be useful as a solving aid to know about minimum and maximum values for the length of each clue number and a way of dealing with missing and required values in partial sums. One such way is to map missing values to 0 and required values to 1, to get a bit-wise string of bits for which bit-wise logical operations can be performed: and, or, exclusive or, not.

Sudoku + Paint By Numbers

Saturday, May 19th, 2007

Sudoku + Paint By Numbers

For me, before I discovered Sudoku there was Paint By Numbers (Nonograms). I was particularly fascinated by painting (shading actually) logically. There are three books of Paint By Numbers Puzzles that I’m aware of: one is authored by Games Magazine, called Paint By Numbers and the other two are by Kathy Weaver, called Art Puzzles By Number and More Art Puzzles By Number.

Battleship Sudoku

Sunday, May 13th, 2007

Battleship Sudoku

Two games in one: Battleship and Sudoku. There are fewer Sudoku clues and added Battleship clues. Use both sources to solve both objectives. The battleships in the fleet are either horizontal or vertical and are totally non-adjacent to each other. The border numbers show the number of cells in a row or column that are contained on one or more battleships.

This variant stems from the 2007 Sudoku Championship Puzzle Instruction Book (in pdf format)

Sudoku Puzzle Creation

Sunday, May 6th, 2007

Sudoku Puzzle Creation:
When your spiffy Computerized, Programmatic Sudoku Puzzle Generator is not available, consider the low-technology, self-involving, self-sufficient random number generator and cell locator tools. You need at least 17 starting numbers and symmetry is required only for the obsessive compulsive (or Virgo people). Don’t start with too many numbers, though, unless creating unsolvable puzzles is your goal.