Watch List notes:

Greece, Constantine I (1913-1917 and 1920-1922), pattern 2 drachmai, 1915, in gold, Paris mint, ΚΩΝΣΤΑΝΤΙΝΟΣ ΒΑΣΙΛΕΥΣ ΤΩΝ ΕΛΛΗΝΩΝ, laureate head left, engraver's name Κ. ΔΗΜΗΤΡΙΑΔΗΣ below, essai to right of date, rev., ΒΑΣΙΛΕΙΟΝ ΤΗΣ ΕΛΛΑΔΟΣ, Greek arms with the badge of the Order of the Redeemer on crowned mantle, ΔΙΔΡΑΧΜΟΝ below with essai to right, plain edge struck with French cornucopia hallmark and 1OR (for .916 fine gold) (cf. Divo P98 and P100 (note); KM-E36), mint state and of the highest rarity, in NGC holder graded PF 64 Ex Hans Schulman auction, 24-26 October 1963, lot 1200 (described as unique) and Spink auction 5, 17 May 1979, lot 254. This coin still appears to be the only recorded specimen.
(Estimate: 100000 - 150000 GBP)