Long-recognised, unwritten jurisdictional norms have seen questions of validity and infringement of registered IP rights reserved to the courts of the country of registration. However, recent attempts have been made by litigants and courts in China, and more recently by commentators and litigants in Europe, to exert extra-territorial jurisdiction in relation to patents. We look at what patentees and/or alleged infringers can do, whether in Europe or the US, to prevent overreach by a foreign court.