Numerous Moslem scholars railed against hoarding and harmful speculation (market cornering and manipulation known as "Gharar"). Moslems were the first to use promissory notes and assignment, or transfer of debts via bills of exchange ("Hawala"). Among modern banking instruments, only floating and, therefore, uncertain, interest payments ("Riba" and "Jahala"), futures contracts, and forfeiting are frowned upon. But agile Moslem traders easily and often circumvent these religious restrictions by creating "synthetic Murabaha (contracts)" identical to Western forward and futures contracts. Actually, the only allowed transfer or trading of debts (as distinct from the underlying commodities or goods) is under the Hawala. "Hawala" consists of transferring money (usually across borders and in order to avoid taxes or the need to bribe officials) without physical or electronic transfer of funds. Money changers ("Hawaladar") receive cash in one country, no questions asked. Correspondent hawaladars in another country dispense an identical amount (minus minimal fees and commissions) to a recipient or, less often, to a bank account. E-mail, or letter ("Hundi") carrying couriers are used to convey the necessary information (the amount of money, the date it has to be paid on) between Hawaladars. The sender provides the recipient with code words (or numbers, for instance the serial numbers of currency notes), a digital encrypted message, or agreed signals (like handshakes), to be used to retrieve the money. Big Hawaladars use a chain of middlemen in cities around the globe. But most Hawaladars are small businesses. Their Hawala activity is a sideline or moonlighting operation. "Chits" (verbal agreements) substitute for certain written records. In bigger operations there are human "memorizers" who serve as arbiters in case of dispute. The Hawala system requires unbounded trust. Hawaladars are often members of the same family, village, clan, or ethnic group. It is a system older than the West. The ancient Chinese had their own "Hawala" - "fei qian" (or "flying money"). Arab traders used it to avoid being robbed on the Silk Road. Cheating is punished by effective ex-communication and "loss of honour" - the equivalent of an economic death sentence. Physical violence is rarer but not unheard of. Violence sometimes also erupts between money recipients and robbers who are after the huge quantities of physical cash sloshing about the system. But these, too, are rare events, as rare as bank robberies. One result of this effective social regulation is that commodity traders in Asia shift hundreds of millions of US dollars per trade based solely on trust and the verbal commitment of their counterparts. Hawala arrangements are used to avoid customs duties, consumption taxes, and other trade-related levies. Suppliers provide importers with lower prices on their invoices, and get paid the difference via Hawala.