Scarce silver tanka of Nasir Al-Din Mahmud (837-864 AH / 1433-1459), Bengal. Large silver coin, measuring 27mm, 10.9 grams. Inscriptions on both sides. Undated, no mintmark. Excellent high grade large and scarce silver coin. This type is among the rarest issues of Mahmud. "The coins of Indian Sultanates" #B427.