Kammala jumla mai zuwa: A farkon yakin basasa na Spain a 1936, yana da shekaru 18, Sanz Bocos ya shiga cikin sojojin Jamhuriyar, a cikin rukunin Antigas, yana farawa a gaban Villanueva del Pardillo, don daga baya a ba shi zuwa
Talavera gaban. Ya kasance wani ɓangare na ƙungiyar da aka aika zuwa makarantar matukin jirgi a Kirovabad, Azerbaijan, inda aka zaɓe shi ya zama matukin jirgi na Polikarpov I-16.