The second type of Danzig ducats of John III: with a bust of the king in armor and crown, with the Order of the Holy Spirit on his chest (rather than in a Roman toga), by the famous medallic artist Höhn.
Very nice, with luster/mirror in the background, only deficient centrally.
The issue was stamped in 1683 (with the last digit of the date punched through). Minted during the period when Christian and David Schirmer were in control of the Danzig mint (hence the lack of initials D-L on the reverse).
Obverse: royal bust in armor, legend in the rim:
IOAN-III D G-REX POL-M-D-L-R-PR-.
Reverse: coat of arms of Gdansk supported by two lions, in the rim legend:
MON-AUREA CIVITAT.GEDAN 1688