A Cash-like Coin of Uyghur Qaghan Boquq

Reference: Francois Thierry Les Monnies de Boquq Qaghan des Ouighours (795-808) ['The coins of Boquq, qaghan of the Uighurs (795-808)'], in:Turcica, vol.30, 1998, pp. 263-278 (in French).
This is a summary of F.Thierry's reference:

    The traditional Chinese and Japanese numismatics ascribe to Mouyu qaghan (759-780) a rare copper coin with a square hole, bearing the inscription Kol bilga Tangri Boquq Uigur qagan. This attribution is based on the opinion of Albert von Lecoq who found the same qaghan's name, Boquq, in a Manichaean manuscript of Turfan. Recently, a new attribution appeared in the Chinese literature: this coin might have been issued by a qaghan of the Uyghurs of Qoco around 947. Some problems of historical or epigraphical origin, however, make us have doubt as to the soundness of these two opinions.
    The main question is not the form of the title, but the meaning of the word Boquq. From the data provided by the bi- or trilingual inscriptions of Wuwei and Karabalghasum Uyghur steles, by Uyghur documents brought back by German expeditions, and by the works of French and Japanese scholars, we come to the conclusion that this coin was issued by Boquq qaghan (795-808), well known in the Uyghur literary tradition as one of the most powerful qaghan, and known as Huaixin kehan in the Chinese sources.