by Mian Ayaz » Mon Jan 05, 2015 10:28 am
The EA sudoku app that comes with Amazon's Kindle will often reject the Saturday (most difficult) newspaper sudoku that is published by the Raleigh NC News & Observer. This last one was found by Stuart's solver to have a unique solution, requiring only a Ywing to solve, but the EA app said that it was unsolvable:
Mian Ayaz