Sudoku fans rejoice! Petr Blahoš has created a fun Firefox extension that brings sudoku headaches and frustration to Firefox.

To play, just select Your SUDOKUs sidebar from the View/Sidebars menu. Select a puzzle from the sidebar and click on >> to open it in a new tab. To place a number, you click on it from the bottom number bar and then on an empty space. The selected number will be highlighted on the board to help you avoid errors. If you’re not sure, right click to place the number as a hint instead.

It helps identify errors like a number repeated in the same column, row or square, highlighting them all as soon as you place the duplicate.

Sudoku ships with 65 puzzles (40 easy, 5 medium and 20 hard), but one of its main features is the ability to grab other puzzles from well known sudoku web sites including WebSudoku, Sudoku Puzzles,  Sudoku online, and a few others.

You simply visit the site and Sudoku will detect the puzzle and prompt whether you want to play it now with the enhanced interface ir provides or save it to play it later. Saved puzzles are stored in the Unrated category.

An option to pause a puzzle and continue it later is planned and will be very welcomed. I would also like to see thumbnails of the puzzles as a the mouse cursor passes over them in the sidebar and a way to turn off the tips displayed at the bottom.

Sudoku is a very nice extension, with some rough edges still there. But minor bugs aside, what it needs is some eye candy to make it more enjoyable and playful.

sudoku 0.9 is available from Mozilla Add-ons as an experimental extension so you will need a Mozilla Add-ons account to access and install it.