This is a 1921 Pattern dirk used by the Reichsmarine, the navy of the Weimar Republic. The dirk features a black spiral grip and a brass hilt with naval insignia. It is a standard naval pattern dirk issued to officers. The Reichsmarine served as Germany's naval force between 1919 and 1935. This dirk was part of the formal dress and ceremonial uniform for naval officers during this period.  Daggers similar to this appear in Wittmann's book on Navy Daggers, from page 195 to 202.  Many variations exist, this one being produced by Alcoso.  Most feature a plain blade - not common to find one with an etched blade.  Condition is excellent, with a perfectly preserved black grip.