Interactive Sudoku for Kindle 2 and Kindle DX - Volume 1 ($0.01), from MobileReference. As you can guess from the title, this "book" doesn't work on the original Kindle, but will on the all the later generations. In addition, I've highlighted their note in the product description: you must have whispernet access and must turn it on as you start each new puzzle. I suspect this will work fine on the international Kindles, but may or may not work well on a US Kindle 2 that is outside the US (even though sporadic reports of these having working whispernet in other countries are starting to appear).Book Description
Our best interactive Sudoku puzzles are now available for Kindle!
Whether you are a novice to Sudoku or an experienced player this collection will sharpen your mind.
Each Sudoku volume contains 20 different Sudoku puzzles: five puzzles for each difficulty level.
The objective a Sudoku game is to fill a 9X9 grid so that numbers 1 through 9 occur exactly once in each row, column, and 3X3 box.
With Mobi Sudoku you can:
* Check your progress at any time. The number of wrong entries will be reported.
* Remove errors. Use it if you feel you made too many mistakes and want to keep your correct entries but remove incorrect ones.
* See the solution
* Reset the puzzle if you want to start over.
* Add a clue if you feel that you are stuck. A single number will be added to a randomly chosen empty cell.
Note: Whispernet wireless needs to be turned on when a new game is loaded. Once a game is loaded, wireless can be turned off to conserve battery power.
