From 2002 to 2011, China ran large surpluses in both the current and capital accounts of its balance of payments, which the People's Bank of China (PBOC) purchased and held at official foreign reserves to avoid nominal appreciation of the currency. Concurrently, with its massive purchases of foreign exchange, the PBOC compelled commercial banks to buy PBOC ‘sterilisation bonds’ and raised commercial bank reserve requirement ratios to avoid monetisation of its foreign exchange purchases and concomitant upward pressure on the price level (that is, real appreciation of the currency). Sterilising foreign exchange intervention, as China did for a decade, constitutes a violation of the implicit rules of a fixed exchange rate regime and as such can be seen as a mercantilist policy of manipulating the real exchange rate to gain, or avoid losing, international price competitiveness—what Corden (1981) termed ‘exchange rate protection’. This paper sets out the simple theory of the costs and benefits of exchange rate protection and provides back‐of‐the‐envelope estimates of their magnitude in China in the 2000s. It also explores the ‘other side of the story’, the decline in US manufacturing employment in the 2000s, which recent literature attributes to a ‘China Trade Shock’ that allegedly resulted from the US granting Permanent Normal Trade Relations (PNTR) to China in 2001. Here, it is argued that the so‐called China Trade Shock resulted from China's sterilised intervention policy, not the granting of PNTR. The implications of these competing hypotheses are considered in the conclusions.