Just a Guess !
Possibly a Japanese Revenue, a prefecture stamp for Inspection of Rice.
Best I can do.
I think you're right, Rod, and I would add that it's specifically from Hy˘go Prefecture. Nicholas's stamp and Tony's example both have "Hy˘go" and "rice" in their inscriptions, and the inscriptions differ only in the denominations. Where the denomination of Tony's example is "1 sack," the denomination on Nicholas's stamp is "50 sacks." The inscriptions on both run from right to left, which is rare nowadays but was common before World War II.