Capture-go is a variant of go. In capture-go the goal is to capture opponents stone(s). Capture Go is easier to learn, but still very challenging game.
Hactar can play both go and capture go. Capture go is easier game for the computer, so Hactar can play it against you without a server. Hactar plays go using a server, this way Hactar has decent strength in go (Note: Hactar Lite plays at beginner level.) You can find more information from <a href="http://gowrite.net/hactar/client.php?lang=en">Hactar home pages</a>.
Internet has a lot of go related material. Some of the best knows links are collected in <a href="http://gowrite.net/hactar/client.php?lang=en&topic=links">Hactar links</a>.
