Sudoku 9 x 9, from concentration to relaxation! Sudoku 9 x 9, from concentration to relaxation! 500 easy to very difficult puzzles designed by Olivier Dupont-Therrien, a new author at Bravo publications! who launched his own production and publishing company of word games for mobile devices, Joueur 2 Studios inc, in 2012. His puzzles are appreciated by hundreds of thousands of French speakers around the world. In the same collection: Relaxation Collection – Mysterious Sudoku by Jacques Lessard.