The Hammer Stradivarius is an antique violin made by Italian luthier Antonio Stradivari (1644–1737) of Cremona.
The back measures 36 cm, bearing the label inside: "Antonius Stradivarius Cremonensis/Faciebat Anno 1707".
It is named after Christian Hammer, a 19th-century Swedish collector who is its first recorded owner.
The violin made its way to the United States in 1911 with violinist and teacher Bernard Sinsheimer.
The Hammer was on loan to violinist Kyoko Takezawa, who performed with it for the next twelve years.