After the Constitutionalists occupied the battlefield on April 4, 1915, their commanders knew that the Villistas were close. As Obregón's troops fortified their defensive positions and waited for the Villista main attack, Villa's forces began to move towards Celaya on April 5. In order to disrupt the movement of Villa's forces, Obregón ordered a 1,500-man element to occupy a hacienda called “El Guaje” near Celaya, to serve as a base to attack the railways that Villa relied upon for movement of his troops. This was a tactical miscalculation, as the majority of the Villista forces were already nearby and immediately attacked the comparatively small Constitutionalist force. As soon as Obregón heard of the engagement, he quickly boarded a troop train to personally reinforce his men at the hacienda. A competent military mind, Obregón immediately realized that this initial tactical error could be the perfect ruse to lure the bulk of Villa's forces into his defensive positions. Obregon ordered his forces to retreat; the Villistas took the bait and pursued the Constitutionalists back towards their prepared positions at Celaya.