Al-mutawwakkil ala'l rahman bahlul shah sultan bi-hadrat Dehli // Fi zaman amir al-muminin khulidat khalifarahu and date 859 (= 1455 CE). 20mm, 9.42 grams. Delhi mint. G/G #D690. 

High-silver billon tanka, excellent quality. Much scarcer than Goron/Goenka indicated.