Watch List notes:

THRACE, Mesambria. Mid-late 5th century BC. AR Hemiobol (6mm, 0.34 g). Corinthian helmet facing / Incuse square. Cf. Karayotov I 7–12 (obols); cf. HGC 3, 1362 (obol); Gorny & Mosch 233, lot 1221. Toned. VF. Extremely rare denomination for issue.