Aart's Blog

Now that Checkers for Android supports a position setup editor, analyzing textbook studies has become a lot simpler. This has increased the significance of the small built-in endgame tablebases of my app as well, as can be seen in the study below. Here, starting from what is known as the "first position" in checkers, Checkers for Android, playing with the black pieces, announces its inevitable loss in 30 moves!

I finished a position setup feature for Checkers for Android , similar to what was already in Chess for Android . This feature allows users to copy interesting checker problems from textbooks or other sources and play from there to improve their game. In addition, I added an option to show the square labels to make playing out variants from textbooks a bit easier for players that are less familiar with the numbering scheme. Since I recently also added a feature to export games as PDN, this implied I also had to implement FEN setup for games that do not start from the initial position. An example is shown below (note the FEN tag, and the empty first ply since it is white's move in the given position). [Event "Checkers for Android Game"] [Site "United States"] [Date "2019.01.19"] [White "Checkers for Android"] [Black "Self"] [Result "*"] [PlyCount "0"] [Setup "1"] [FEN "W:W9,K32:B13,K1...

Although the Certabo electronic boards are mainly intended for chess, the flexibility of the identifying chips makes them suitable for 8x8 checkers as well (draughts, or American checkers, with slightly different rules from e.g. 10x10 international checkers). Therefore, I am planning to add support for Certabo boards in Checkers for Android as well. The 34 identifying chips can be used for the 24 regular pieces and 10 kings for promotion (using special purpose pieces avoids stacking the regular pieces). A 3D printed set can be used for this purpose (a continued hat-tip to my brother-in-law Gerard Harbers for making all the chess and checkers sets for me!). The general idea is illustrated with this picture. Please let me know if you like this upcoming support!

I can't believe it, but Chess for Android just passed its ten year anniversary! In November 2008, it appears for the first time on the -then-called- Android Market, together with Reversi for Android. Checkers for Android was soon to follow. The Android Market was later renamed Google Play . Working on this GUI has been a lot of fun, even though it took all spare time away from further developing my chess engine BikJump. But pioneering support for third party engines (at a time nobody was compiling for ARM), both UCI and XBoard, accessing endgame tablebases on SD card, adding PGN and setup features,simplifying engine setup through Chessbase compatible format and the Android Open Exchange format, using OCR apps to read chess positions, translating text to other languages, maintaining an online manual , and recently adding support for Certabo, DGT, and Millennium electronic chessboards has been just as rewarding. I have compiled many engines for Android back in the days, ran ful...

I am enthusiastic to announce that I am rolling out version 5.9 of Chess for Android on Google Play . New features include: Configurable tags for PGN export (player, ELO, event) Ability to offer draw or resign (click king twice to enter menu) Support for Certabo electronic chessboards The application now supports connecting to any of the DGT, Millennium, and Certabo chessboards (let me know if there are others). I have a second instructional video on this topic on YouTube. As usual, looking forward to your constructive feedback!

Besides the Millennium and DGT, Chess for Android now also supports the Certabo electronic chessboards. I hope to roll out a next update soon, after more rigorous testing. Unlike the other boards, the Certabo board does not necessarily come with chess pieces. Instead, a set of 34 identifying chips is provided, which can be attached to the bottom of pieces in any chess set (which means that, unlike the other board, the GUI must first match newly attached chips with the right pieces). Since I did not have a spare set, I asked my brother-in-law, Gerard Harbers, who just bought a fancy new 3D printer, to print a full chess set for me. He enthusiastically got to work! The pieces have some spare room at the bottom, perfect for placing the identifying chips.

New releases for both Checkers and Reversi for Android . Both games made some improvements in the notation display, most obvious the use of parenthesis for the alternating moves (suggested by Rein Halbersma), a better column layout, and improved "scrolling" while navigating. Also, both games now support exporting the game to the clipboard or via sharing with another program. For checkers, the PDN (portable draughts notation) is used, for reversi something similar to PGN (portable game notation). For checkers this also required "disambiguating" captures using an intermediate square (which should cover most normal games).

Folks that know me probably saw this coming, but Checkers for Android now also has a notation window and full game navigation, just like Chess for Android and, recently, Reversi for Android. All three games have the same look-and-feel again! Unlike the algebraic notation in chess or reversi, checkers uses a numbered notation, explained in detail in The Checker Maven  (note that, for simplicity of display, my checkers app always just shows the "from" and "to" square for each move or capture, even though technically intermediate squares are sometimes needed to disambiguate multiple jumps). At first glance the numbering may seem a bit confusing, but the notation becomes easier with practice.

It has been a while since I added major features to Reversi for Android , but I recently added something I had been planning for a long time: a notation window and full game navigation, similar to Chess for Android. The result is shown below. No more artificial restrictions on the undo, one can simply go back and forth in the full game, and try different strategies to learn from one's mistakes! An interesting factoid is that Reversi uses a slightly different board orientation for the algebraic notation: the a1 square is in the upper left corner with the h8 square in the bottom right corner. This goes a bit against my chess intuition, but obviously I had to follow the Reversi convention.

Around the holidays I am finally getting some spare time to implement new features for Chess for Android . I am actively "in the zone" working on: The ability to offer a draw or resign during an ongoing game. Since the UCI protocol does not provide this feature, the GUI will accept the draw simply based on past evaluations of the position. The ability to change the users name and ELO rating, which will appear in the header for all user games that are saved in PGN format to the SD card. The ability to connect to FICS , the free internet service. This is of course the most work and currently still in prototype stage. The first release will probably start simple by just allowing to watch demo games.