Psychiatry, like most professional fields in Russia, gained its legitimacy from its ability to serve the Tsar and later the Bolshevik party. The militarised nature of these governments meant that psychiatry would have to prove its worth to the military. This study will cover Russian/Soviet military psychiatry from its first practical experience during the Russo-Japanese war to its greatest test during the Great Patriotic War 1941-45. Throughout this study, the continuity between Russian and Soviet military psychiatry will be emphasised. For example, psychiatry's materialist school dominated throughout this period and that Russia's acceptance that psychiatric casualties will occur allowed them to focus their resources on treatment rather than prevention.