The five-chu pieces were replaced in the early T'ang dynasty (618-907) with coins just over two chu. From this point, dynastic year names were formally used to name the coinage.
唐初五銖錢被廢行，另外鑄「開元通寶」錢，每枚重二銖四絲。自此後年號被正式用來當錢幣名稱。