Sperrle's staff had no file information on Guernica. Richthofen earmarked the town's Rentaria Bridge for attack, but he seems to have been more interested in Guerricaiz six mles (10 km) south east of Guernica. Richthofen referred to this town as "Guernicaiz" in his diary. The Republican left flank had to retreat through Guernica and the air staff earmarked it for bombing. Richthofen's diary entry, dated 26 April 1937, documented the purpose of the attack. His plan was to block the roads to the south and east of Guernica, thereby offering a chance to encircle and destroy Republican forces.