The epoxidation of an alkene to give an oxirane is taught in introductory organic chemistry. Formulating an analogous mechanism for such reaction of an alkyne sounds straightforward, but one gradually realises that it requires raiding knowledge from several other areas of (perhaps slightly more advanced) chemistry to achieve a joined up approach to the problem. I had indeed hinted in a previous post that the mechanism for oxidation of acetylene to ketene might be an interesting arrow pushing challenge to set a bright tutorial group, and it was that self-hint that has led me to here. I now explore how my “arrow pushing” intuition stands up to a computational examination.