They are from the "æ˜å’Œ" "showa period" . The "showa" period is from 1926-1989 but these are at least 30 years old as Japanese stopped using them once the word processor was invented.
This would be perfect for using as a stamp with ink or for stamping clay etc.
This stamp is the Kanji (Chinese character) for "院" "in" = "school, courtyard, yard, court".
It measures 2cm long (long enough to be able to get a nice grip) and 1.5cm wide. The Chinese character itself is about 1.5mm wide. It is made of metal.