My Japanese d-i-l’s dad had a pistol in his antique collection. A matchlock allegedly from the early 19th century. Japanese firearms technology was ‘frozen’ after the kicked out the Portuguese. Don’t know if it was legal for him to own it.
My dad was introduced to a Japanese gun smith in Yokohama who did excellent engraving on rifles and shotguns. Local cops checked on his work shop every day.
He engraved a Mod 11-48 Remington and filled the groves with silver from a US half dollar.