When a piece is pregnant, he must be rushed to the Hospital Square (h1) within nine turns (the gestation period). When the piece reaches this square, he can give birth by rolling 4 or more. The colour of the offspring depends on the colours of the parents[1]. The offspring piece is considered a child for the next 20 turns and cannot attack, but after this it is a fully-fledged piece. The type of piece in question is decided by D6.

If the piece fails to reach the Hospital Square in time, the gestation period ends and play continues.

Rooks cannot become pregnant, and instead lay a chess egg.

  1. Pregnancy, Chess and You, Harvard Press, 2006