This coin illustrates an aspect of the production process, as it has very clear marks of the process. The usual explanaition for the octagonal or "rosette" hole on some Far Eastern coins, is that the additional four corners on these coins are unintended indents from the square metal rod on which the coins were placed, to facilitate the filing of the edges of the coins. This particular coin shows considerable deformation of the metal (around the four extra corners), caused by the coin being forcibly placed on, or removed from, the rod. This coin is more thin in fabric than most Sung coins, which probably explains why the deformation is so clearly visible on this coin, but not on Sung coins.

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