promise
約束 — Institutions
Settling to make good later.
Zhongtong Yuanbao Jiaochao noteYuan, Zhongtong era (from 1260)
Banknote of the Banque Royale1720
25 Ruble Assignat (1769)1769
⚠ A banknote, ultimately, is a promise written on paper. As long as the promise continues to be fulfilled, the paper functions as currency. The moment it becomes clear it will not be fulfilled, it reverts to being just paper.