The Pulsar Chess Engine plays Chess, with levels, and six variants of chess. Its most played option is still chess. I originally developed Pulsar as a Winboard chess engine/computer program starting in 1998, and between 2002-2009 taught it to play the variants it knows. It was released on mobile for the first time in 2014 and on Android in 2019. The variants are Chess960, Crazyhouse, Atomic Chess, Loser's Chess, Giveaway(also known as Suicide Chess – goal is to lose your pieces) and Three Checks. In chess it values mobility and open play more than closed positions. At variants, each has its own style. 



Pulsar logs all its games and they can be opened in the Game menu. Newest games are on top and if the game is a chess game, Stockfish engine analysis is available. 



Pulsar includes levels for all its games and the rules of Chess and each chess variant are included as well. It's add free. It defaults to chess at Easy if the users just starts playing, otherwise go to the game button and choose new game to configure a more specific game. Last game type played is saved on restart of the app. There are some choices for board colors and chess pieces as well as the apps background color. There are also show books moves and show thinking options in settings.



The board in Pulsar Chess is Accessible by Talkback, for the blind and visually impaired. Only direct tapping is supported, not swiping. Tap on a square, and it will speak what's on the square such as "e2 - white pawn". Double tap to select the square with Talkback on. There is also speak move. This speak move and tap on square info is in English as well as Spanish, Italian, French and German. Talkback can normally read text on buttons and labels etc, but a board is a collection of images. To be accessible, the board has to be programmed to return text when the tap is in the space of a square.



Pulsar started as a chess program and over time learned variants. It remains an interesting chess only program if the users it not interested in variants and I tend to just play chess. I ran it extensively on two chess servers testing the app against strong players and also testing how to handicap it on handicapped computer bots. The ratings that appear on the board when selecting from the first 8 difficulty levels are estimates based on what I saw running it at various strengths.



On game / new game if play vs the computer is unchecked the user can play in two person mode which I've found useful when I have a device and want to play a chess game but no chess board with another person who is present.

 

The Atomic Chess variant in Pulsar follows ICC rules and has no concept of check and king can castle in check. In Crazyhouse the user can use a turn to drop on board any of the pieces they have captured and the piece palette with the drop pieces appears to right of board. 



The engine code on all platforms, mobile and Computers is pulsar2009-b. If users follow the support link or visit developer website, they can get pulsar2009-b binaries that work on all the different computer operating systems in Winboard Protocol supported clients. I have decided to not release an Android binary at this time. Partly because we use the Winboard Protocol and the UCI official protocol does not support all the variants Pulsar plays so it would not run in UCI clients.

Added a new level after Difficult
Added Morphy and Carlsen game collections to the exiting collections
Expanded translation in app
Set a default size for opening first time on Chromebook