Optimistic observers have heralded the current, unprecedented global tax reforms as the beginning of the end of the tax haven system. Whether this is the case depends on the (already doubtful) robustness of the proposed reforms and the responses of multi-national corporations and states that have an interest in sustaining international tax competition. Measuring change in this area is no easy task, not least given the ambiguous nature of corporate tax avoidance. Ireland is an ideal example of ambiguity in the world of corporate tax. This is because it has features of a tax haven, and yet, also has features that do not fit the classic description. The thesis studies a particular skill within Ireland’s Foreign Direct Investment (FDI) skillset that is hidden. This is the skill of playing corporate tax games well. A theory of global tax games is developed, defined as institutionalised, reflexive modes of strategic interaction among states and corporations, constituted by the configuration of four fundamental dimensions of tax. These dimensions are the rate of taxation, the jurisdiction which makes the claim, the capital owner responsible for any payment, and the definition of the return upon which the tax is claimed. These dimensions are configured in different ways. Each game has a distinctive ‘internal’ mode of coordination where actors compete, mutually adjust, cooperate and contest over tax claims, over an uncertain period of time, using tax rules and other institutional mechanisms. This approach tracks the evolving and interacting state-corporate engagement across the tax dimensions as a form of ‘infrastructural power’ (Braun, 2020), represented by tax games. By bridging the ‘state-centered’ perspective of the ‘classic’ tax competition literature and the transnationally focused literature associated with corporate ‘global wealth chains’ (Seabrooke and Wigan, 2017), a firmer analytical basis is offered to explore potential change in global tax.