The economic impact of the West on China has long been a subject of debate among students of Chinese history. Despite numerous books and articles, however, a consensus has yet to emerge. Part of the reason for this, I believe, is that the more analytical contributions to the debate have been too sweeping in their historical coverage, while those with a more limited time perspective have been insufficiently rigorous in their analysis. The aim of this paper is to renew this debate, but to do so by a method that will, hopefully, avoid the pitfalls of the past. Specifically, I intend to employ an explicitly theoretical framework to examine the facts of a particular period—the 1860s. This decade is especially important since it immediately followed the expanded opening of China by the Treaty of Tientsin in 1860. The analytical framework employed—economic theory—is applicable to any period in modern Chinese history, but as the data examined are drawn mostly from the 1860s, my conclusions, strictly speaking, are applicable only to that decade. For reasons discussed below, however, I strongly believe these conclusions to be applicable to the entire period from 1860 to 1895.