Interference (chess) Interference (chess) In the game of chess, interference occurs when the line between an attacked piece and its defender is interrupted by sacrificially interposing a piece. It is a chess tactic which seldom arises, and is therefore often overlooked. Opportunities for interference are rare because the defended object must be more valuable than the sacrificed piece, and the interposition must itself represent a threat. In the position at left, White to play will apparently be obliged to retreat the knight from f5, because the squares to which it could advance are all guarded. However, the interference move 1.Nd6+ interrupts the
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