Query: What was the mass of the wuzhu coin?
Context: In 144 BC Emperor Jing abolished private minting in favor of central-government and commandery-level minting; he also introduced a new coin. Emperor Wu introduced another in 120 BC, but a year later he abandoned the ban liangs entirely in favor of the wuzhu (五銖) coin, weighing 3.2 g (0.11 oz). The wuzhu became China's standard coin until the Tang dynasty (618–907 AD).