The exchange (chess) The exchange (chess) The exchange in chess refers to a situation in which one player loses a minor piece (i.e. a bishop or knight) but captures the opponent's rook. The side which wins the rook is said to have "won the exchange", while the other player has "lost the exchange", since the rook is usually more valuable. Alternatively, the side that has won the rook is "up the exchange", and the other player is "down the exchange". The opposing captures often happen on consecutive moves, although this is not strictly necessary. It is generally detrimental to lose the exchange, although
Evolution of the horse horse", "Orohippus" was not a true horse and did not live in the mountains. It resembled "Eohippus" in size, but had a slimmer body, an elongated head, slimmer forelimbs, and longer hind legs, all of which are characteristics of a good jumper. Although "Orohippus" was still pad-footed, the vestigial outer toes of "Eohippus" were not present in "Orohippus"; there were four toes on each fore leg, and three on each hind leg. The most dramatic change between "Eohippus" and "Orohippus" was in the teeth: the first of the premolar teeth were dwarfed, the last premolar shifted in shape and function