BENGAL: Rukn al-Din Kaikaus, 1290-1300, AR 1/18 tanka (0.60g), NM, ND, G-B91, inscribed only 'adl on obverse, rukn on reverse, VF, RR. There are two fractional tankas for Kaykaus, a 1/12 tanka with a weight standard of 0.90g and his name "kaikaus" on the reverse, and what seems to be 1/18 tanka of 0.60g with his title "rukn" on the reverse (both have "'adl" on the obverse, as do all later issues). The same two types continued under Shams al-Din Firuz (1300-1320), inscribed "firuz" on the 1/12 tanka, "shams" on the 1/18 tanka. Finally, the 1/18 continued under Ghiyath al-Din Bahadur, with "Ghiyath" on the reverse (G-B110, there is no reported 1/12 tanka for Bahadur). These denominations are known only for these three rulers. Examples filed on CoinArchives and Zeno with their weight confirm these two denominations.

Estimate: USD 80 - 120