I understand your desire to use backlighting to highlight the chess pieces, and it worked well for that, but the resulting glare on the chess board spoils it.
The concept of this shot fits the challenge well. The focus seems a little soft and the contrast could be bumped up a little, but the translucence of the pieces may make that a little difficult. (Do you realize that the rook and knight are reversed?)
Opposition, yes, opposite sides, yes. The shot has potential but the lighting is too harsh in some areas and muted in others and the front peices are out of focus. DOF is a good thing at time but for this shot I would really like to see it all in focus. A 4
The colors look very subdued and unnatural in this picture. If this was done in PS, I don't particulary care for the effect. If it came from the camera, you may want to re-evaluate the use of backlighting for this shot. The reflections on the floor distract from the main subject. A table cloth or sheet or something under the chess set might have removed or at least softened these reflections.
The blues in the darker chess pieces come off quite well. I like the streaks of light and shadow off reflective surfaces coming from an unseen window. I wonder what rules this game has and wonder what kind of game it is. The depth of field is necessary to keep the pieces and the board in focus, but the wood surface on which the board lays does not have sufficient appeal to support the focus that is placed on it.
I thought about doing something like this but decided not to. Nice job. The softness and reflections are somewhat distracting, but I think if you work on it a little bit you could have a winner...
focus could be better (larger DOF). lighting/colors could be better (less strong light from windows?). wood table just doesn't work. looks a little twisted, especially at the bottom. 2 or 3 degree rotation would help