This article deals with the problem of international arbitration awards whose reasoning is unduly summary. The author, marking the distinction between investor-state and commercial arbitration, discusses the reasons for reasons in international arbitration. The annulment system of the ICSID Convention is briefly addressed, through the instance of the Lucchetti case, with particular focus on the extent of reasoning to be provided when declining or affirming jurisdiction— stressing the inacceptable character of arbitrators merely assuming jurisdiction in the absence of consent by one party. Finally, the author addresses the question whether a decision by an annulment committee on a failure to state reasons should be considered a review of form or of substance.