Japanese coin/token

The image shows a round, ancient coin with a square hole in the center, typical of many East Asian coins from historical periods. The surface of the coin is worn, and remnants of gold-colored material highlight the engraved symbols or characters on it. There are four main characters arranged around the central square, possibly an indication of its origin or value. Additionally, handwritten digits "18915/1939" are present along the outer edge, possibly a catalog or collection reference number. The coin's patina suggests significant age, and it rests against a dark background, emphasizing its historical and cultural significance.