Teach Yourself Advanced Sudoku and Kakuro
by Nick Afka Thomas

Teach Yourself Advanced Sudoku and Kakuro (Teach Yourself)

If you are serious about solving the really hard Sudoku puzzles and branching out into Samurai, Kakuro and Killer Sudoku this is the book for you.

The author starts with defining terms so that the techniques can be understood. XYZ Wings, Magnetism, Pincer Movements and the like are not self-evident.

He also recommends a method to mark up a puzzle. Instead of the typical style he calls 'Pencil marks' where you write all possible numbers for a cell (as small as you can) in that cell, he suggests a technique modeled after betting in Roulette. The Roulette notation is cleaner and does a better job in showing dependencies between cells.

For example, if a cell could have the values 1, 4, 5 or 8 those 4 numbers would be written in the cell in traditional pencil marking. But with Roulette Notation, maybe you know that the cell has to have a 4 or a 5. The new markup language identifies that more clearly.

The book includes some practice puzzles to let you try out the technique that was just explained. It may take several re-readings and attempts to grasp a technique. Some just don't seem logical but they work.

There are variations of Sudoku that are also covered such as 16x16 grids instead of the usual 9x9 or Samurai Sudoku. Samurai Sudoku consists of two normal Sudoku grids that share one nonet. The lower-right nonet for the top grid and the upper left for the bottom grid. It's a whole 'nother smoke, believe me.

I like Kakuro because it throws a little arithmetic into the mix. In Kakuro, the clues tell you the total that the cells add up to. You cannot repeat any of the digits in one clue. So the maximum is 45 (the sum of 1-9).

Some clues are trivial. If you have 2 squares and a sum of 17, one must be 8 and the other 9. But 27 in 5 numbers could have 11 different answers. It's a challenging puzzle and the author explains it well.

Killer Sudoku is a combination of Sudoku and Kakuro that is still a little advanced for this puzzle solver. When I'm ready, I know that this book will get me some useful techniques to the solutions.

What are you reading?  Let us know at dan@greatlakesgeek.com