I bought this as a souvenir when I traveled to Kochi Prefecture and had it stamped at the Ryoma Post Office. It seems to be a Ryoma Post Office exclusive! I bought a lot and had them stamped, so I'll sell them if anyone is collecting them. The date is October 19, 2017. There are 3 in total. If you're interested, please let me know how many you'd like! This price is for one stamp. Please check my profile.