An ancient system of moving money based on trust. It predates western bank practices. Although it is now more associated with the Middle East, a version of hawala existed in China in the second half of the Tang dynasty (618-907), known as fei qian, or flying money. In hawala, no money moves physically between locations; nowadays it is transferred by means of a telephone call or fax between dealers in different countries. No legal contracts are involved, and recipients are given only a code number or simple token, such as a low-value banknote torn in half, to prove that money is due. Over time, transactions in opposite directions cancel each other out, so physical movement is minimized. Trust is the only capital that the dealers have. With it, the users of hawala have a worldwide money-transmission service that is cheap, fast and free of bureaucracy. From a government's point of view, however, informal money networks are threatening, since they lie outside official channels that are regulated and taxed. They fear they are used by criminals, including terrorists. Although this is probably true, by far the main users of hawala networks are overseas workers, who do not trust official money transfer methods or cannot afford them, remitting earnings to their families.