The premise of beggar-thy-neighbor policies and currency wars is that currency depreciations lead to export growth. This premise, however, is far from validated as the existing economic literature largely either fails to find significant trade flow effects of currency fluctuations or finds that these effects are only minor. We revisit the question of whether currency fluctuations are systematically associated with trade flows using rich and unique firm level Chinese customs data on China-US trade over the 2000 to 2011 period that allows us to consider firm involvement in processing trade and firm dynamics in both export and import markets. Our firm-level based estimation of trade elasticities suggest that the China-US trade balance strongly responds to changes in the CNY/USD rate. This finding is particularly pronounced when we distinguish between ordinary and processing firms. Our results thus suggest that the influence of exchange rates on trade flows is stronger than previously thought and add insights to the policy debate on beggar-thy-neighbor policies and currency wars by, at least in principle, validating the underlying premise of such policies.