In Ancient Greece, during the period of minting the first coins, the stamps were primitive: if the obverse was decorated with a more or less clear image, then on the reverse there was an indented trace. Around the 6th century BC, they began to use square-shaped stamps, the imprint was called an "incuse square" (quadratum incusum). On some copies, the image is blurry, the edge is uneven, the surface is smooth, on others you can see simple patterns inside the square. Over time, more complex designs appeared on the reverse, like on the obverse. Everything depended on the level of minting in each city.
A typical simple incuse square can be seen on staters from the island of Chios, dated to the 6th-5th centuries BC. The obverse depicts a sphinx, next to it is an amphora - Chios was where they made wine, which was valued throughout Greece. On the reverse is a square divided into four parts, the shape of the coins is very rough.
In Miletus at the turn of the 6th–5th centuries BC, obols with an incised square with a floral pattern in the center were minted. The obverse depicts a lion's head. These coins date back to the reign of Aristagoras of Miletus.
In the Milesian colony of Proconnesus, they made their own obols with a horse's head on the obverse and an image of an oinochoe inside an incised square on the reverse. An oinochoe is an ancient jug with a handle, intended for serving wine at festivities.
In Lycia, a country in the southern part of Asia Minor, several types of obols were minted. The reverse depicts the head of a gorgon, the ancient triskelion symbol, the head of Hercules, etc.
Source:
britishmuseum.org
