This is the famous Walter Hagen concave wedge, which was outlawed by the USGA in 1931. This club personally belonged to World Golf Hall of Famer Roberto De Vicenzo. The face is engraved "Doc's Cuchara", which translates to Doc's Spoon. We don't know much about how De Vicenco came into possession of this club, as it had been banned for decades before he began to play golf. But we do know that it was part of Roberto De Vicenzo's personal collection.