1 Cash - Anonymous Kaiyuan Tongbao, Lan

The Kaiyuan Tongbao series, introduced in 621 under Tang Taizong, became so dominant that later emperors simply continued striking it anonymously rather than issuing coins under their own reign titles — a practice essentially without precedent in Chinese monetary history. The "Lan" variety, identified by a crescent-shaped mark on the reverse, belongs to a classificatory system still not fully resolved among scholars; whether these marks denote specific mints, furnace supervisors, or batch controls remains contested. Hartill places this type firmly in the late Tang period, when central authority was fracturing under warlord pressure and regional mints operated with increasing independence.