Blocking, unblocking, and safety plays in bridge

John Terence Reese (28 August 1913 – 29 January 1996) was a British bridge player and writer, regarded as one of the finest of all time in both fields. He was born in Epsom, Surrey, England to middle-class parents, and was educated at Bradfield College and New College, Oxford, where he studied classics and attained a double first, graduating in 1935. Source: Wikipedia