Complex sentence: In his role as an arbiter he directed the two Piatigorsky Cup tournaments of 1963 and 1966 and later was involved in adminstration in the US Chess Federation.
Split into simpler sentences: In his role as an arbiter he directed many chess tournaments, such as the two Piatigorsky Cup tournaments of 1963 and 1966. He was later involved in adminstration in the US Chess Federation.