Barnes Defence arises after 1.e4 f6. ECO code: B00.

Named after Thomas Wilson Barnes (1825–1874), who played it against Paul Morphy. The move weakens the kingside (particularly the e8–h5 diagonal) without contributing to development. After 2.d4 e5 (attempting to challenge the centre), Black's position is already compromised. The defence is considered one of the worst responses to 1.e4.