Antique Japanese Tsuba
A Tsuba is a hand guard for a nihonto (the native term for "Japanese sword"). The symbol in red to the left if one of the kanji for "tsuba" (there are a couple).
The tsuba is probably the most collected item in the realm of Japanese sword parts (togosu). Many are highly valued and some are even classified as national treasures never allowed to leave Japan.
Originally tsuba were simple iron plates made by the same craftsman that forged the sword. As time progressed, they took on a more artistic value and separate craftsmen were contracted to create tsuba and the other Japanese sword accouterments. All this culminated in the late eighteenth century with the production of strictly ornamental soft metal (alloys of copper, silver and gold) tsuba.
Collectors these days often focus on a particular school or set of schools, and although the later highly decorative tsuba are prized, many prefer the austere simplicity of the earlier "Goto" style iron tsuba.