Thái Đức was the reign title adopted by Nguyễn Nhạc, the eldest of the three Tây Sơn brothers whose rebellion dismantled Nguyễn lord control over southern Vietnam in the 1770s. Nguyễn Nhạc proclaimed himself emperor at Quy Nhơn in 1778, establishing a short-lived central domain while his brothers pushed north and south. The crescent privy mark on this cash distinguishes it from the plain type — a common Tây Sơn practice for differentiating mint output or issue batches, though the precise administrative logic behind it remains debated among Vietnamese numismatists.
Thái Đức was the reign title adopted by Nguyễn Nhạc, the eldest of the three Tây Sơn brothers whose rebellion dismantled Nguyễn lord control over southern Vietnam in the 1770s. Nguyễn Nhạc proclaimed himself emperor at Quy Nhơn in 1778, establishing a short-lived central domain while his brothers pushed north and south. The crescent privy mark on this cash distinguishes it from the plain type — a common Tây Sơn practice for differentiating mint output or issue batches, though the precise administrative logic behind it remains debated among Vietnamese numismatists.