dofutoshiki.com features a unique interactive play window with a wide range of capabilities including:

Works in any modern browser without requiring any plugins (including Internet Explorer, Firefox and Safari) Unique digit and grid resizing code - try it and see! Unlimited full undo and redo - makes solving much less stressful, and means finger trouble doesn't ruin the game! Fast entry by pushing number keys to enter big/small numbers; press again to toggle Push 0, backspace or delete to clear a grid entry Hit SPACE to toggle solution/pencil marks, or click on the relevant option Double-clicking on a solo pencilmark number will place it as a solution digit (this is particularly handy with the auto-remove feature) Background saving via AJAX/XML/PHP/MySQL backend with live feedback Intelligent placing of valid digits based on initial grid clues Auto-add pencilmarks Auto-prune small numbers Check your solution (and point out empty cells too) Show invalid moves Show incorrect moves (also glows numbers in IE) Generated from PHP using MySQL database backend Arrow keys and TAB/SHIFT-TAB to move around Or click to move around Click on the entry cursor to remove it if you wish for aesthetic purposes Reveal solution - and also highlights the entries you had wrong (try it - it uses small green numbers) 'Please wait' message for clean screen whilst loading Can cope with any grid dimensions Adaptable to different puzzles - see for example dokakuro.com And more!

If you wish to license the player module for use on your website or other outlet then please contact gareth@dofutoshiki.com.