First up is the Sharper Image Chess Companion, model SM460. If the relative lack of information about it on the internet and very rare appearance on eBay is any indication, it must have not sold very well. However, it is an excellent pocketable portable for the advanced beginner up to the advanced occasional player. But where did it come from?
Answer: The Sharper Image SM460 is a gray-colored version of the Mephisto SuperMini above. It is rare to find the SuperMini on the American eBay though it makes occasional appearances on the German eBay. These are very nicely designed units with all of the requirements for an optimum pocketable for those under a club level: ELO circa 1400-1450, mini-size, overall intuitive design, easily accessible place to store captured pieces, nice basic opening book and the ability to show position evaluation (something that I think is invaluable for all players up to and including club level players).
The SuperMini superseded the Mephisto Mini which looks almost the same, but is a weaker unit and has no book. The Mini seems to crop up on eBay more frequently than the SuperMini. BTW: The Mephisto Mini has its origin from the Fidelity Tiny Chess unit.
Next up is the Excalibur Viper (above) which, like the Sharper Image unit, is rarely seen on eBay and for which there is almost no mention on the internet. Where does it come from?
Answer: The Excalibur Viper is a repackaged Novag Amethyst and they are the very same in every respect except for the nameplates. (The above is actually the Novag Amethyst Plus which is similar in strength to its predecessor, Amethyst, but has gray/blue color on the membrane keys rather than red and also has a different group for each level, one using a 'best move' and the other using a random selection of 'good moves'.
The Novag Amethyst (and, of course, Excalibur Viper) is an attractive unit (and has a minor similarity to the design of the far more advanced Novag Jade/Jade II). However, it is weaker than the Mephisto SuperMini with an ELO circa 1350, has a minimal (some might say, relatively useless) opening book, is a size above what could be called pocketable and does not have position evaluation information.
However, there is one good reason to own a Novag Amethyst or Excalibur Viper: They use exactly the same pieces as the Novag Jade/Jade II.
