Sigma Chess - 6.1.6

I’m a registered user of both Sigma Chess and Vektor3 for years and have also purchased the much touted Chessmaster 9000. Though SigmaChess could receive a makeover (Vektor3 rules in this section), the playing strength is unsurpassed - and THAT is what makes a good chess program! Chessmaster 9000 has lots of features and nice graphics but is slow, buggy, and not as strong as Sigma Chess (in a test I did it lost 10:0 against Sigma HIARCS). Also, quite frankly, the support received by Feral/Zonic on Chessmaster 8000/9000 has been appaling and is non-existing. The HIARCS engine is, hands down, the most advanced chess engine out there and well worth its money if you can beat Sigma Chess on its own engine (which most of us won’t be able to). So, for those out there looking for fancy graphics and a nice game of chess, go with Vektor3. More advanced features and graphics at cost of playability and strength, pick up Chessmaster 9000. But if you’re after a chess challenge, then Sigma HIARCS is the way to go - and yes, you will need to register for HIARCS separately, which is not the developers fault.

I paid for the pro version at 6.03 but my license doesn't entitle me to use the HIARCS engine as registered. Pro enables more features over the lite/free version BUT it doesn't buy a license to use HIARCS in registered mode. Take note that this extra purchase raises the price of Sigma Chess by £19.99. If you like Sigma in its current form them the $20 is a good enough deal but consider buying Chessmaster 9000 which comes with a huge amount of extras..