This paper discusses the creation and use of the new Macquarie Laws of War Corpus. The corpus consists of the 110 documents of international war law stored in the International Committee of the Red Cross treaties database, starting with the 1856 Declaration Respecting Maritime Law and ending with the most recent amendment to the Rome Statute. The new MQLWC is hosted at the Sydney Corpus Lab, via its CQWeb interface, which allows for searching of frequencies, concordance lines, and collocations. The (...) corpus can also be downloaded for offline processing in other popular concordance programs, such as #Lancsbox and AntConc. This paper introduces the corpus, describes the process of assembling the data, and explains its limitations. The paper then demonstrates some of the ways the data can be explored using the concept of 'military necessity'. The MQLWC contributes to the growing use of corpus linguistics in legal studies, and will be of particular relevance to scholars in the field of international war law. (shrink)