Travel money string - 546 Chinese perforated coins from different time periods pulled onto a string (formerly a twisted hemp string) and closed to form a ring. 546 perforated coins, so-called cheese coins (chin. 文), were usually pulled onto strings in China. Cheese coins are old coins made of brass, bronze, copper or very rarely iron or tin or lead with a mostly square and rarely round hole in the centre. A string of five hundred coins was called a tiao; three tiaos in turn equalled approximately one tael silver bar, the largest Chinese currency unit, which was not itself represented by a coin.