These are Japanese stamps called "Hanko" or "Inkan". In Japan, it is common to use one of these in place of a signature in many situations. For government forms and banking, a person would have to register their unique stamp to have it associated with them. I believe these are ready-made stamps with common Japanese surnames that would be used in less formal situations, like signing for a package delivery. Each stamp is ~6 cm long with a 1 cm diameter. There is a gold line along the side indicating the top of the stamp (so you don't accidentally stamp it upside down). I have about 300 of these. I will be updating the available "sizes" as I catalogue more of them. This may take awhile since I don't know very many kanji and the words are mirrored on the stamp face. Feel free to inquire if you're looking for a specific word or name.