Watch List notes:

IONIA, Uncertain. Circa 600-550 BC. EL Stater (20mm, 16.53 g). Phokaic standard. Chimaera standing left / Two incuse squares of unequal size. BMC Ionia 41 = GPCG 18 = B.V. Head, "Metrological Notes on the Ancient Electrum Coins struck between the Lelantian Wars and the Accession of Darius" in NC 1875, pp. 285–8, pl. X, 9; Rosen Sale 73 = Pozzi 2369; New York Sale XLII, lot 154 = New York Sale XXX, lot 142. Minor edge splits, some die rust. Good VF. Extremely rare, one of approximately five known, of which at least two are in public collections (BM and Landesmuseum).

From the Jonathan P. Rosen Collection. Ex Roma XV (5 April 2018), lot 140 (hammer £22,000).

The common weight standard and similar style of incuse punches that this issue shares with the coinage of the "Shield Series" (see Triton XXIII, lot 392–3), suggests that they may be related.