In October 1936 he was promoted to lieutenant colonel and was designated head of the General Staff of the Forces of Defense commanded by General Jose Miaja, head of the Junta de Defensa de Madrid created to defend the capital at all costs after the transfer of the Republican government from Madrid to Valencia. In this capacity he prepared an effective defense plan for the city that prevented its fall. Afterwards, his fame as an organizer increased. As head of the Central Army HQ, he demonstrated outstanding performance in the planning of the main operations developed by the mentioned Army, in the battles of Jarama, Guadalajara, Brunete and Belchite.