Countermark

https://rpc.ashmus.ox.ac.uk/countermark/1227 
GIC
NAK monogram
rectangular 
 

Coins with this countermark

Number Image TypeNumber CoinNumber VolumeNumber
RPC I, 1657 Show 1657 33 1
RPC I, 1657 Show 1657 41 1
RPC I, 1657 Show 1657 42 1