May one separate the black chess pieces from the white ones? The statement of the gemara that we have been discussing the past few weeks only mentions types of food. Although the Taz entertains a possibility that borer is only prohibited with foods, he rejects this on the basis of a comment by Rashi, that refers to a prohibition of borer with regards to a non-food item.
However, there is another angle to examine. Tosfos here says that in general, borer should only apply when one has a food and the unwanted mixed in; yet, our gemara refers to two types of food! He concludes that when one wants only one of them, the other is considered like and intrinsically unwanted part of the mixture, and it is therefore prohibited to separate it. According to this, it would be permitted to separate the chess pieces! Although there is a mixture, because both are equally wanted and they just need to be separate, it is permitted even for later use.
The Rambam specifically discusses separating two items, of which both are wanted. He learns that neither one need be considered “unwanted.” Rather, the very fact that you want to separate them is enough to prohibit the separation. According to this, it is obviously prohibited to separate the chess pieces, except for immediate use. We rule in accordance with the Rambam.
