Imperial German Wurttemburg Model 1889 Officer's Degen or straight sword from about 1889 to about WWI; unusual folding right knuckle-guard (some are without this feature entirely); also an unusual double-fullered blade (both sides). Scabbards are usually black-enameled.
This sword is very similar to the Prussian Model 1889 Officer's Sword with notable differences to the cup pattern.
This pattern of sword was used by Bavaria, Prussia, Saxony, amd Wurttemburg - the only basic differences being the Royal Cypher/Heraldic Crest on the guard and perhaps occasional unit inscriptions found etched onto the blade.