This piece is a numismatic amulet or charm of Japanese or Chinese origin, known as eisen (絵銭) in Japanese. These objects are generally not official currency, but rather charms or good luck tokens, often cast in bronze or brass, and presenting various symbolic images.

Details of the amulet

Type: Amulet or numismatic charm (eisen).

Origin: Probably East Asia (Japan or China), where the use of central hole parts is historically widespread.

Material: Brass or bronze, as the visible patina suggests.

Pattern: The visible side features a fish jumping over what appear to be waves or natural elements (mountains, aquatic plants), a common motif in Asian art and symbolism for luck and prosperity.

These pieces are prized by collectors for their cultural significance and artistic know-how, rather than for their monetary value.