This brings us to a discussion on how to classify chess playing software. There are several ways to do this.

We could have started from the viewpoint of someone who wants to buy the best product for a specific task across similar platforms. This would be the case if you're looking for a product to use while traveling or on vacation.

We could also have started from the viewpoint of someone who has a specific brand in mind, but wants to buy it for the most effective platform. In fact, there are not many products available on multiple platforms. ChessGenius is the outstanding exception, with versions for a wide range of platforms. Chess Tiger and Fritz are sold in both desktop and heldheld categories, although we doubt that the versions compete against the same product in the other category.

We started instead from the viewpoint of someone who wants a product for a specific platform. This assumes that anyone looking for a chess program already uses a computer where chess will be another widget to add to the office, leisure, and other software products used daily.

Given a specific platform, there are several factors which influence the buying decision. The two most important are undoubtedly ease-of-use and playing strength.

Aside from a few comparisons of board displays, we found neither ease-of-use comparisons nor objective measurement criteria. Neither did we find any attempt to determine ratings or to compare playing strength. It appears that this area is wide open for pioneers who have the time and the patience to compare these many products with each other.

One final note : although this article targets commercial programs, we found nothing for Linux and Unix. The chess software for this important computing family is the domain of the hobbyist. This deserves a separate article, because we know that non-commercial chess software -- freeware and shareware -- is a big subject and can't be covered briefly.