The Chess base is a very great app I used it daily it’s show you the games from 1800 to 2018 its a best chess training app its quite difficult for new people but they show in their site I purchased chess app from play store its Worth me 500 bucks aprox but for 500 bucks it’s a legendary app the support & service by them are fabulous you can find any opening their1.you can find any thing theri about chess 2.they provide you india t-shirt you can by from their site chessbase.co.in 3 . You can find information in depth in that site you can anylisis your game by it if you know how to use it. It’s became very easy I suggest all to use it . Its work well don’t take loding time its the best chess app I ever used the best for training . Use it’s too much help full !