Hmm. I do like the idea of a 'chess track'. Or maybe even a chess Skill -- maybe alloting everyone 1 additional skill point, and then adding 'Chess' to the skill tree:
-1 points = how do the horsies move, again?
0 points = heard of the game, know the basic moves.
1 point = played a few games way back when -- novice level.
2 points = played a bunch of games -- chess club level.
3 points = can hold one's own in a tournament.
4 points = Can occasionally win a local or state tournament.
5 points = 'Expert' level, can usually win smaller tournaments and can compete in larger ones.
7/8 points = 'International Grandmaster' level, the incumbent world champion Flints and his challenger Petrovitch would be here.
There should be some trappings that are focused on the game, but also others that can be used outside of it so the skill doesn't become totally useless whenever the characters aren't around/watching/trapped in/etc a chess game.
Trappings could be:
'Chess player'. Self explanatory, controls how good the character is at chess.
'Strategy knowledge'. "What to do when there's nothing to do." Sort of a longer term Investigation, rolls could be used to help either determine the strategy of other characters, or to help figure out what good strategies would be at a certain point. Useful both on and off the board.
'Tactical knowledge'. "What to do when there's something to do." Maybe some kind of Assessment bonus, or maybe a bonus in combat for things like figuring out which of three thugs should be attacked first. Useful both on and off the board.
'Style analysis'. Chess specific trapping; allows the ability to determine a player given a game based on knowledge of their style (or, alternately, determine that a player is not playing normally and Something Is Up).
And then there could be stunts that assign one particular trapping to another, like usual (i.e., "Chess Scholar: you've studied the game extensively and memorized thousands of openings, endgames, and completed sequences. You can use Scholarship instead of Chess for the 'chess playing' and 'style analysis' trapping.' 'Actor on the Board: your ability to use body language to trick and deceive invariably lures opponents into disasters. You can use Performance for your 'chess playing' trapping.' 'First-hand combat knowledge: you've fought a lot, and it's given you a great knowledge of tactics. You may use Fists for the 'tactics' trapping.')
Thanks for the ideas. You all have given me a lot to think about (and I agree that the idea to just have an Elo rating number was probably a bad one).