WinBoard is one of the most advanced Chess interfaces in existence. It provides full support for all major forms of Chess, and allows you to play those over the internet. WinBoard for JAWS is a version of WinBoard made accessible to the sight-impaired. Unlike most other Chess software, it can be fully operated through the keyboard, and uses the JAWS speech synthesizer to report information that cannot be automatically recognized by screen-reader software because it is in displayed in graphical form (such as the Chess board). Many commands, available through shortcut keystrokes, can make WinBoard for JAWS recite various aspects of the board position. In addition, some events, such as the opponent moving, will be announced spontaneously. This makes WinBoard for JAWS an ideal tool for the blind Chess player. And most importantly, WinBoard is completely free, and is being actively developed.
WinBoard can be used for many different tasks. It can be used to play against other people over the internet, as client to Internet Chess Servers like FICS (freechess.org), to analyze your games with the strongest Chess engines available on the planet (e.g. the commercial engine Rybka or the free Houdini), to play against the computer (using somewhat less formidable engine opponents to keep it interesting), to have different engines play against each other, or simply to read through Chess games you obtained. It can do all those things for standard Chess, but also for other Chess variants, like Chinese Chess (Xiangqi) or Japanese Chess (Shogi).
WinBoard can optionally provide an enormous amount of information on the Chess game in progress. You can open auxiliary windows, for instance one containing the list of moves, and another containing the best continuation of the game as judged by a Chess Engine. It can annotate games you fed to it, by having an engine think on all positions in the game, and including the engine's opinion with each move, in the form of a numeric score and the best sequence of moves from it. All this information is accessible through the screen reader, as it is in normal text form, and the Tab key can be used to quickly navigate between the windows to reach the sought information.
Note that WinBoard is a general chess interface, i.e. a go-between for Chess-playing entities; it does not think up chess moves or evaluation scores by itself, but it just passes them on between the user and the entity that provides the moves. For having the computer calculate moves, WinBoard can connect to so-called engines. WinBoard supports the major standards for such engines, U C I and WinBoard protocol, and literally hundreds of engines that use those protocols are available. This includes the major commercial engines like Rybka, HIARCS, Shredder, Deep Sjeng, Naum, but also free engines like Houdini, Stockfish, Komodo, Firebird, Toga, Fruit, Crafty. These are the strongest Chess-playing entities in the world, and you would use them to quickly get answers about the absolute truth of a given chess position.
It is not much fun playing against such monsters, though, unless you enjoy being ripped apart. But fortunately hundreds of engines are available for WinBoard, most for free, all with very different playing styles, ranging in strength from monsters to absolute morons with negative Elo rating. The standard installation package of WinBoard for JAWS contains Fruit 2.1 as a super-strong engine to analyze your games, and Fairy-Max 4.8 as a very challenging, but beatable opponent for mere mortals. And it is always possible to dumb down engines by many hundreds of Elo points by handicapping them with time odds, so they cannot think as many moves ahead as they would otherwise do. And if Fairy-Max at 0.1 sec per move is still too tough for you, there are many much weaker engines available for download on the internet, such as Usurpator 2, Youk or N E G 0.3d.
There are also engines that specialize in Chess variants, like suicide chess, Chinese chess, etcetera. The included Fairy-Max engine already plays some variants, next to standard chess. Other engines that play many Chess variants are Pulsar and Sjeng.
Download WinBoard 4.5 for JAWS
Download Usurpator 2 (weak) Chess Engine
Download Youk (weaker) Chess Engine
Download N E G 0.3d (weakest) Chess Engine
Download page of Pulsar Chess Engine (plays Chess 960, Crazyhouse, Atomic Chess)