WESTERN ASIA MINOR, Uncertain. 5th century BC. AR Hemiobol (6.5mm, 0.31 g). Head of bridled horse right / Rough incuse square. Cf. SNG Kayhan 745 (head left; uncertain Ionia or Caria); cf. Klein 332 (Kyme in Aeolis); cf. Tzamalis 88 (cruder style with mane and neck indicated by series of dots; Thraco-Macedonian mint). Toned, light porosity. VF. Well centered.
While such coins are generally assigned to an uncertain Thraco-Macedonian mint, the style of the current coin is more refined than any of the horse types in Tzamalis. "Horse/incuse" types were almost certainly minted at multiple locations, and a mint in (western?) Asia Minor is the most logical choice, though Kyme is not likely.