Lviv mint sixpences are among the coins very rarely seen in the trade. Appreciated with such a high note as MS64, they are practically unheard of. This is confirmed, among other things, by the NGC census, in which it is the highest grade for all vintages of Lviv sixpences.
This has to do, among other things, with the nature of their issuance. While the early sixpacks of 1656-1657 are wartime issues, those of 1660-1663 bear the hallmarks of a mass issue - a wide variety of varieties, a multitude of stamps, frequent imperfections in minting or sheet defects. Hence their difficulty in obtaining MS notes.
The present sixpence, in addition to its beauty, is also a very rare variety.
It is a coin with a V-type bust of the king (wider, with a mantle fastened with a brooch in the form of a rosette), with the reverse distinguished by an ornamental type of shields (profiled, with a double, thick outline, decorated with bows on the upper edge).
Rated with a high degree of rarity in Lukasz Ciura's catalog (equivalent to R4/R5 in Kopicki's Index).