ID Help Please - Frog Pottery - Japanese

Hello. Can anyone recognize the maker or tell me anything regarding this pottery? It is small and has some calcification that can be cleaned. There is some minor crazing so I do not believe that this is a new item. It appears old. It also came from an estate where a lot of the pottery items were pre-1960.  The maker's mark on the bottom appears to be partially covered by where the kiln stands were at. It could be SI or SH or ???  The frogs appear to be hand made.  Thank you in advance!