Watch List notes:

MACEDON. Akanthos. Circa 460-430 BC. Diobol (Silver, 12 mm, 1.31 g, 9 h). Head of Athena to right, wearing crested Attic helmet adorned with an olive wreath. Rev. Α-Κ / Α-Ν (the final two letters upside-down and retrograde - boustrophedon) within the four granulated quarters of an incuse square. AMNG III/2, 39 (same dies) = de Luynes 1544 (same dies). Pozzi 734 = Pozzi (Boutin) 1494. Tselekas, Period E, D51a (OD42/RD43 this coin). A wonderful coin of a beautiful and refined Classical style. Lightly toned. Minor die fault on the obverse, otherwise, about extremely fine.
From the "Collection sans Pareille" of Ancient Greek Fractions, ex Aufhäuser 8, 9-10 October 1991, 52.