It is a excellent app for chess. The unique problem, and because that I am not giving five stars, is that it doesnt have the "drag and drop" for the pieces, while most of the other chess app have. So, we need to touch a piece and the square where we want to put it on. It is not exactly a big problem, but people which uses others chess apps too are accostumed with the drag and drop for moving pieces. I think the developers could think in adding that feature in the app. All the other features are perfect, interface ( very beautifull ), control of strength, setup position, save games, takeback moves for study, playing with rating x with no rating, everything is excelent. I recommend the app.