Single Comment

Here's my take after a little thought. The point assignments probably need work.

A game which is a form of chess, is one which includes all of the following properties:

1. A game of movement and capture, rarely of placement (2 points)
2. Bilateral symmetry and equality of material (1 point)
3. Functionally differentiated pieces (2 points)
4. Capture by replacement (1 point)
5. Win by capturing a definitive singleton (royal piece) (3 points)
6. A Turn-based game (1 point)
7. A Two-player game (1 point)
8. A game of Complete information (1 point)
9. Played by moving pieces between discrete positions (2 points)
10. The players can move one piece per turn (1 point)
11. One piece type is more abundant than the others, quite weak, moves uni-directionally and can promote (1 point)


[1-5 (but not the point system) taken from: Parlett, D. S. (1999). The Oxford history of board games. Oxford: Oxford University Press. p. 277.]

[6-11 (but not the point system) taken from H. G. Muller's post on chessvariants.org commenting system.]

Suggested terms:

Chess-game: 16 points (all properties)
Chess-like game: 10-15 points (many properties)
Chess-related game: 4-9 points (some properties)

Note that many chess variants are (according to this scheme) chess-like or chess-related games.

Examples:

Go                = 0 + 1 + 0 + 0 + 0 + 1 + 1 + 1 +0/1+ 1 + 0 = 5/6
Checkers          = 2 + 1 + 0 + 0 + 0 + 1 + 1 + 1 + 2 + 1 + 0 = 9
Losing Chess      = 2 + 1 + 2 + 1 + 0 + 1 + 1 + 1 + 2 + 1 + 1 = 13
Extinction Chess  = 2 + 1 + 2 + 1 +0/1+ 1 + 1 + 1 + 2 + 1 + 1 = 13/14
Ultima            = 2 + 1 + 2 + 0 + 3 + 1 + 1 + 1 + 2 + 1 + 0 = 14
Progressive chess = 2 + 1 + 2 + 1 + 3 + 1 + 1 + 1 + 2 + 0 + 1 = 15
Grand chess       = 2 + 1 + 2 + 1 + 3 + 1 + 1 + 1 + 2 + 1 + 1 = 16