The Swedish Defence Research Agency (FOI) has, on behalf of the Swedish Armed Forces, developed and conducted a game on the theme Management Accounting in Crisis and War. The purpose was to examine how the Armed Forces' work with budgeting, financial monitoring, and annual accounts functions in relation to other key government agencies during a severe crisis or war. The game was carried out with participants from the Swedish Armed Forces, the Swedish Defence Materiel Administration, the National Fortifications Agency, and the Swedish National Financial Management Authority. The results show that the state's system of management accounting is fundamentally robust but not fully adapted to a situation in which ordinary processes and systems are disrupted. In particular, the need became clear to ensure continuity in payment flows, a clearer division of responsibilities between agencies, and practical support for the application of existing regulations during heightened readiness. The authors assess that management accounting needs to be strengthened through: simplified accounting procedures that can be activated in a crisis, guidance on how sensitive financial information should be handled, education and exercises for accounting and finance functions, as well as clarified mandates and decision-making channels. The next step involves developing practical procedures and expertise to ensure that the state's management accounting systems function even under conditions of crisis and war.