Mao Zedong famously said that “political power grows out of the barrel of a gun.” As he was someone who looked to the Russian Revolution for inspiration while engaged in a war to liberate his country from Japanese occupation, his view was understandable. Yet power can be exerted in different ways and can be most effective when it is hidden, with decisions made behind closed doors, or even invisible, so that the decisions one person makes are influenced by another without them realising it. The growing literature on what are termed “the commercial determinants of health” pays particular attention to the hidden and invisible forms of power, whereby large corporations use various methods to shape thinking about what are appropriate responses to the health consequences of their products. In the accompanying article, Susan Greenhalgh describes how the Coca-Cola Company came to dominate obesity policy in China even though its influence was obscured behind the public face of intermediaries