A few weeks ago about the only variant to Sudoku was another number puzzle called Karuro. Oh yeah, there were also some larger ones of 16 X16 cells, some circular, etc. Now, it looks like a feeding frenzy around the Games and Puzzle section of the bookstore. Not to mention the plethora of hand held electronic Sudoku games on e-bay. The only thing competing for attention is the raft of books started by the monster hit Da Vinci Code. This author has put out several other Sudoku books and is one of the most popular amongst what is becoming many. For a quick look of 5 different types of “Grid Puzzles” you can’t go wrong with this book, Monster Book of Japanese Puzzles: Masyu, Nurikabe, Hitori, Sudoku and Kakuro. It is anybody’s guess how many other types we’ll see in the near future. But I can tell you this, I have been a ‘puzzle nut’ for 60 years and have a collection of over 500 puzzle books and there are literally hundreds more of variations on grid puzzles. And then there’s the whole world of Magic Squares simply put you isn’t seen nothing yet. There is also another book that has recently appeared, “The Sudoku Code” by Francis Heaney that combines Da Vinci with Sudoku for those who like mysteries and puzzles combined. You can purchase this book at Amazon.