Play chess online at FICS or ICC, play the Pulsar Chess Engine on or offline with chess and variants like Chess960 with levels, and use the Explorer with an opening tree book based on 345k over the board games and analysis which also works offline. There is In-App help. For online play, if no account, use the Connect as Guest button to play unrated. FICS accounts are life time free accounts. Diamond supports Dark Mode and has no ads. The On-Board chess program with difficulty levels available on and offline plays Chess, Chess960, a form of shuffle chess, and variants such as Crazyhouse, Losers and Atomic Chess. The Explorer Tab which works offline or online with certain restrictions while playing, offers an Opening Tree based on 345K over the board games were both players are rated over 2300. The move table view can be toggled to show analysis and PGN games including the players log file can be loaded. Chess openings are named after a few moves are made. There are 10 PGN game collections available in app that include Morphy 1858, Fischer’s best games, a Capablanca and Kasparov collection, and a range of game collections from classical too modern to be viewed with the opening book and analysis, on and offline. Guests can play on FICS and ICC unrated, but only watch games on FICS. FICS is the original Free Internet Chess Server, and a sign up link is given in the console when connecting to both servers as a guest as a resource if a user wants to play rated or chat. FICS is non profit and ICC has a trial or free level, but with the ICC trial 50 chess videos can be watched in-app. On FICS, guests and members can use the Training tab of Find a Game Board Option. The Diamond Chess board features engine analysis with one click when observing a chess game or examining one, such as when going to Actions - Examine last game. There is also has a Load PGN option which includes some grandmaster game collections that can be opened on FICS board as well as in Explorer. Diamond Chess saves all played games. Multiple games can be up at once, with navigation through the next and previous buttons. Diamond has chess and the server's variants such as Chess960, a form of shuffle chess known as wild fr on FICS, Crazyhouse, Losers, Atomic Chess, and Giveaway or Suicide Chess. Guests can play any unrated game type. Diamond Chess has an accessible chess board to use with Voice Over for the visually impaired. With voice over on, if a user taps a square it will speak its contents such as "e4 empty" or "e4 white pawn" and there is a speak move with Voice Over on. Members on both FICS and ICC can join channels and chat with chess players online in the Diamond Chess's Main View by tapping the Channels button. In Shouts on FICS there is also blikII, an AI bot who responds to his name. His last response to me was "blikII(TD) shouts: I appoint you ambassador to Fantasy Island!!!". The in-app help in this view has more tips on how to chat including a guide on which channels chat more. ICC, the Internet Chess Club, has free levels and free guest access. FICS, the Free Internet Chess Server, is entirely free.