Countermark

https://rpc.ashmus.ox.ac.uk/countermark/947 
GIC 831
denominational mark Η
circular 
6.5 mm 
Uncertain (Uncertain)
Possibly the same as GIC 830. If so, it was probably countermarked by mistake, because an attempt seem to have been made to apply 830 to coins of Smyrna only. The style of the H is cruder than is usual for 830, so 831 may form a separate group. 
List of countermarks View on a map

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC X, — (number not assigned), type ID 61529 Show 1687 4 10