Vintage Japanese Branding Iron Oil Yakiin F477 by VintageFromJapan http://www.etsy.com/listing/90759196/vintage-japanese-yakiin-branding-iron
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 "abura / yu" which means "oil".
They are from the "昭和" "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.