This is a small iron pot, possibly a sukiyaki bowl, from Mizusawa, Iwate Prefecture in the Tohoku Region. It contains an inlay reproduction of the Kan'ei Tsūhō ("寛永通寳") coin from the Edo era. This particular item may be mid-century, it has the makers mark on the bottom of the pot and an aged label in the lid, but we were unable to transcribe it
About Nambu Ironware: "Nambu ironware finds its roots in the mid-17th century, emerging alongside the Nambu samurai clan's rule over northern Iwate Prefecture. The Nambu clan invited adept foundry artisans from Kyoto and beyond to shape intricate pieces such as Buddhist altars and tea kettles" (Oitomi.com)."Today certified Nambu ironware manufacturers are mostly located in Morioka or Oshu cities and collectively they form a total of 74 factories" (TokyoWeekender.com)