A single vertical line, representing one set of ten. Analagous to the archaic characters 廿 (twenty) and 卅 (thirty). Possibly originally a picture of a needle, now written as 針.

Evolution

Oracle script

(~1250-1000 BC)

Bronze script

Early Western Zhou (~1000 BC)

Seal script

Shuowen (~100 AD)

Clerical script

Eastern Han dynasty (25-220 AD)

Regular script

Modern

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