對中國發動鴉片戰爭的英國，其所謂「自由貿易」的內容，乃是廢除對交易物資、對象、場所等限制，進出口稅率並非最重要的問題。自1850年清政府建立釐金制度後，英國方面對實現「自由貿易」的目標，開始轉向中國國內的徵稅。對此，清朝方面僅將貿易、「關稅」視為財源，尚未形成保護關稅和關稅自主權的概念。至1870年代，以北洋大臣李鴻章有力幕僚為中心，保護關稅才開始成為政策及輿論的討論焦點。1876年簽訂的《煙台條約》曾規定租界內免除釐金。至1881年9月，中西雙方擬定清朝方面允許免徵洋貨釐金，西方則同意將進口稅率由5%提高為10%，所謂「裁釐加稅」協議幾乎達成。「加稅」和「裁釐」原是兩件不同的事務，在現實談判中運用「裁釐加稅」概念者，以馬建忠為始。基於保護中國商人以奪回利權、致富求強的觀點，馬建忠建議廢止釐金，並相應地提高關稅稅率。然而，這次談判最終不但未達成協議，且直到二十世紀，中國關稅制度都未再出現變革的轉機。在十九世紀末的中國形勢下，西洋的「自由貿易」與清朝的「保護關稅」概念只能以「裁釐加稅」的形式相結合，且只停留在觀念層次，不易落實。為探究其原因，本文將重新考察產生、並持續推行釐金制度的清代中國社會經濟結構。

"Free trade" was the rallying cry of Great Britain as it started the Opium War against China, and the meaning of this cry was the elimination of all restrictions on the goods, clients, and locations of trade. Tariffs as such were not the most important issue for the British. Since the Chinese government had established the likin system in 1850, the British regarded inland taxation in China as a primary obstacle to surmount to achieve their goal of free trade. The Chinese regarded trade and "custom duties" only as financial resources, and had no concept of protective tariffs or tariff autonomy. Only in the 1870s did protective tariffs begin to be discussed as policy options among the staff of Li Hung-chang, the imperial commissioner for Northern Ports. In 1876, China and Britain concluded the Chefoo Convention, which provided that the settlements at the treaty ports were to be exempt from likin taxation. Until September 1881, it was agreed that the Chinese would accepted the exemption of the likin on foreign imported goods, while the foreign countries would agree to raise the tariff from 5 to 10 percent. In other words, a policy of so-called "ts'aili-chiashui" (exempting likin and raising tariffs) was almost agreed to be carried out. At the beginning, Li approved of raising tariffs but objected to exempting likin, and we can see here that chiashui and ts'aili were two different things, not related to each other. In the actual negotiations, ts'aili-chiashui was discussed as a twinned concept due to a memorandum from Ma Chien-chung to Li. From the viewpoint of recovering the concessions and searching for wealth and power, Ma proposed raising the tariff and in return exempting likin to protect Chinese merchants. Thus, his idea of protective tariffs related chiashui to ts'aili, and the idea of a unitary ts'aili-chiashui was established at last. However, no final agreement was reached in these negotiations, and, as well, from that time to the twentieth century, China never had an opportunity to revise tariffs. Under the conditions of the nineteenth century China, the Western idea of free trade and the notion of protective tariffs of the Chinese were coupled to create the mode of ts'aili-chiashui, but at the same time this was only a conceptual plan, not practical one. In order to understand the reasons for this, it is necessary to reexamine the structure of Chinese society and economy during the Ch'ing period that first brought about and maintained the likin system.