唐代發行貨幣，鑄量較大的有三種，一是開元通寶，一是安史亂時鑄造的乾元重寶，另一種則是背字的開元通寶型態，俗稱會昌開元，因為鑄於武宗會昌年間(841-846)之故。其中會昌開元錢背文至今已發現二十三種，分別是京、昌、洛、荊、襄、鄂、潭、益、梓、興、潤、宣、丹、廣、桂、福、永、平、藍、兗、越、梁、洪，是晚唐、五代主要使用的貨幣。這些背文－京、昌（淮南節度使以會昌年號背文）、荊、襄、鄂、潭、益、梓、興、潤、宣、福、兗、越、梁、洪代表各藩鎮；洛、丹、永、平代表鑄錢監；廣、桂可能是廣州、桂州（嶺南節度使和桂管），也可能是錢監（廣陵監、桂陽監）；藍則至今不詳，宋人意為藍田縣。但無論如何，這些地名卻沒有與中央分庭抗禮的河北諸藩鎮。河北諸鎮在史思明時曾鑄造少量的當百大錢，與唐室的乾元重寶錢競爭，不過這些鑄量實在不足以擔負稅賦和通貨的需求量，那麼河北地區主要的交易媒介又是什麼？和兩稅法時代的唐中央控制地區相比，河北是什麼樣的狀態？本文希望由這個切入點研究河北的經濟型態。
There were three major currency of Tang Dynasty: Kai-yuan-tung-pao, Chien-yuan-tung-pao, and Kai-yuan-tung-pao with can-ed words on backs which was nick-named "Hui-chang Kai-yuan" for it was published dury the period of Tang Wu Emperor's Hui-chang years (841-846). Since then, there are twenty three kinds of words carved on Hui-chang currency, forming a special layout of copper-money. It was the main currency in Tang and Wu-dai period. Among the twenty-three carvings, "Ching" (京)、 "Chang" "(昌)、"Ch'ing" (荊)、 "Hsiang" (襄)、"Er" (鄂)、"Tan" (潭)、 "Yi"(益)、"Zsu" (梓)、"Hsing" "(與)、"Jun" (潤)、"Hsuan" (宣)、"Fu" (福)、"Yen" (兗)、"Yueh" (越)、"Liang" (梁)、"Hung" (洪) represented as each Fen-chen, "Lo" (洛)、"Tan" (丹)、"Yun" (永)、"Pin" (平) meant the currency cawing bureau, and "Kuan" (廣)、"Kuei" (桂) might be named after Kuan Chou and Kuei Chou or two currency bureau Kuan-lin (廣陵) and Kei-yang (桂陽). As to the "Lan" (藍) still remains unknown, how ever people in Sung said it meant Lan-tien. Nevertheless, there were not any names of those Fen-chen in Ho-pei which were as politically powerful as the central government. During the period of An-shih rebellion, Fen-chen in Ho-pei had made few hundred-coins that were competitive to Chien-yuan chung-pao of the central government. However, the amounts were not affordable for local tax and currency, and not possible to be the major exchange unit in Ho-pei. Then, what situation would it be in Ho-pei by comparison to the central controlled areas in period of Two-taxes system? That leads to the key point of this article.
