The usage of cash coins in the Chinese pseudoscientific practice of feng shui is commonplace influencing many superstitions involving them. Believers in feng shui believe in a primal life force called qi (or chi) and apply their beliefs to the design of residential houses, as well as to commercial and public buildings, sometimes incorporating cash coins into the flow of this supposed qi.
Cash coins are category of ancient Chinese coinage which are typically round in shape and have a square central hole, these coins were used as the main currency of imperial China between 221 BC and 1912 AD. In feng shui cash coins are believed to be able to attract wealth and prosperity and to ward off "evil spirits" (煞氣, shà qì). However, placing them an outward facing position is believed to cause misfortune and placing them at the wrong places supposedly attracts "evil spirits" and poverty. For this reason special care is usually taken by feng shui practitioners when handling cash coins. While classic Chinese coins can come in a huge variety, particular categories of them enjoy more celebrity status than others, this is because Feng shui practitioners believe that some cash coin inscriptions are more auspicious than others, for example the Qianlong Tongbao (乾隆通寶) is commonly seen as an auspicious inscription because it was produced in a period of military and economic ascendancy in Chinese history, while the Xuanhe Tongbao (宣和通寶) is seen as inauspicious because it was produced during a more tumultuous era.
Feng shui practitioners typically place cash coins that are strung together somewhere in their house or in a cash register to supposedly attract wealth, alternatively they may carry them around as an accessory or place them in their wallet for good luck. A common way cash coins are used in feng shui is as a set of 5 coins known as the "Five Emperor Coins" (see below), these are often used as counters to hanging beams or exposed pillars. When used for such purposes, the 5 coins are often tied together with a red string (as red is seen as an auspicious colour) so as to charge them with yang energy. When combined with Taoist beliefs cash coins could be strung in the shape of a sword to scare away evil spirits.
Because of their common association with feng shui, cash coins are commonly referred to as feng shui coins in English.
The application of cash coins in feng shui should not be confused with the use of cash coin and cash coin-like amulets as "lucky charms" outside of feng shui, their usage in traditional Chinese medicine, or their usage in traditional Chinese fortune telling.
Chinese cash coins
The cash coin became the main standard currency of China in 221 BC with the Ban Liang (半兩) and would be produced until 1912 AD there with the Minguo Tongbao (民國通寶). Cash coins are characterised by their round outer shape and a square center hole (). The hole in the centre of the coins allowed them to be strung together.
Originally cast during the Warring States period, these coins continued to be used for the entirety of Imperial China. The last Chinese cash coins were cast in the first year of the Republic of China. Generally most cash coins were made from copper or bronze alloys, with iron, lead, and zinc coins occasionally used less often throughout Chinese history. Rare silver and gold cash coins were also produced. During most of their production, cash coins were cast, but during the late Qing dynasty, machine-struck cash coins began to be made. As the cash coins produced over Chinese history were similar, thousand year old cash coins produced during the Northern Song dynasty continued to circulate as valid currency well into the early twentieth century.