A constructed racial otherness of the enemy distinguished colonial warfare from other modes of fin-de-siècle warfare, while it constituted at the same time a unifying element across different empires. It gave rise to a general culture of permissiveness and the fashioning of an imagined ‘native mind’, two preconditions for a specific body of knowledge on colonial warfare to emerge. This featured specific prescriptions as to what colonial warfare was to do, denoted here as the five ‘basic imperatives’: colonial warfare had to generate a ‘moral effect’ on the opponent, it had to be ‘bold and offensive’, it had to create a ‘lasting peace’ by using heavy force first, it had to ‘punish’ and, increasingly, it had to produce high death tolls (the ‘big bag’). The chapter explains how all these imperatives pushed towards extreme violence and demonstrates how all were present in very similar forms in the British, German and Dutch empires. For each, the origins, development and empire-specific appearance are discussed. With a transimperial corpus of colonial manuals as main source base, it is also shown that there was a further convergence in this body of knowledge around 1900.