This is a vintage branding Iron called a "yakiin". These were/are used on wood, leather...food...anything you want to brand. Please see the last picture to see an example of how it can be used.
I think they would look fabulous if used in pottery as a stamp. Also...I think they could be used with ink but as it is metal, the image wouldn't be as smooth and clear as a rubber stamp -please keep that in mind if that is how you want to use it.
This is "usu" (in Kanji character) which means "mortar".
They are from the showa period" . The "showa" period is from 1926-1989 but these are at least 30 years old.
This is made of iron. Please look at the pictures carefully
It measures 19cm long x 2 cm (the stamp) wide.
For more branding irons click here http://etsy.me/2cF0fg5
This post first appeared on Japanese Stickers Fabric Vintage Items And By From, please read the originial post: here