The choices in the chess minigame represents moves you can make. The capital letter represents which piece you're moving, for example R means Rook, Q means Queen, N means Knight etc (no letter means pawn). The rest is coordinates on the chess board (see the 1,2,3s on the vertical and the a,b,cs on the horizontal) corresponding to where you're moving the piece. An X means you're taking a piece while moving.
Fastest way to get through them are trial and error, though, with the quicksave and quickloads