These are authentic recreations of Ching era currency, which were round coins with a square hole in the center. The convention was used to allow people to string coins together into sets of 10, 20, 50 and so forth. However, in Taoist thought the round coin and square hole represent heaven and earth. The circle of the coin represents the heavens, while the hole is the earth at the center. Tradition holds that putting three coins together and binding them with a red string or ribbon completes a Taoist trinity of Heaven, Earth and Humanity. The tied coins are then a kind of good luck charm for bringing prosperity and fortune to the holder. The beliefe is the lucky coins should be placed in a wallet, purse, check book or any in the wealth corner of your home to promote wealth. Reorient hand ties each set of coins with a fine and durable bright red nylon string to insure long lasting luck. Hang a set by your office door or on the monitor of your computer if you use it for work.