Another useful guide from law firm HFW is this one, which starts by defining letters of credit – a contract widespread in international trade by which a bank agrees to pay the beneficiary upon the happening of a specific event or, in connection with the export of specific goods, against the presentation of specified documents. They offer security of payment for and receipt of goods to contractual counterparties who may be in different jurisdictions to each other – and who may be contracting to buy and sell goods which are located in a third jurisdiction, or which are in transit. A feature common to all types of letters of credit is that money is raised on the documents, not on delivery of the goods. The Uniform Customs and Practice for Documentary Credits 600 (or UCP 600) are international rules published by the International Chamber of Commerce (ICC) with the aim of standardising international banking practice in respect of letters of credit.
http://www.hfw.com/downloads/HFW-client-guide-letters-of-credit.pdf
