Norma relacionada
Practice Relating to Rule 37. Open Towns and Non-Defended Localities
Section A. Establishment of open towns
Belgium’s Law of War Manual (1983) states: “an area is considered as an ‘undefended area’ or as an ‘open town’ when it is undefended to the point that it can be taken without a single shot or without any losses (e.g. due to the presence of mines)”. It adds that the presence of wounded military personnel and weapons does not change the status of the area as an open town or undefended area. The manual points out two procedures to obtain the status of “open town”, namely, a unilateral declaration or an agreement between the belligerents. 
Belgium, Droit Pénal et Disciplinaire Militaire et Droit de la Guerre, Deuxième Partie, Droit de la Guerre, Ecole Royale Militaire, par J. Maes, Chargé de cours, Avocat-général près la Cour Militaire, D/1983/1187/029, 1983, p. 30.