of Trikoupis Group (5th, 12th and 13th divisions) retreated to the west without problems. Trikoupis Group spent the night of 28–29 August around Olucak (). At the same time the Frangou Group was under pressure by the incoming Turkish IV Corps. Frangou's units were deployed in line around Başkimse (). After repeated failed efforts to establish wireless communication with the Greek I Corps Frangou ordered his units to begin their withdrawal to Dumlupınar position at 16:00 hours. At 05:00 hours on 29 August all units of Frangou Group had reached the positions around Dumlupınar, in good order despite the pressure of the Turkish IV corps. The battle of Hamurköy-İlbulak Dağ (29 August 1922) During the night of 28–29 August the Turkish VI Corps (of the Second Army) had advanced to the west and reached the north of Trikoupis Group. The Turkish V Cavalry Corps and the First Army's units (I, II and IV Corps) advanced towards the Greek Frangou and Trikoupis Groups. The Turkish I Corps advanced towards Dumlupınar and made contact with the Greek Frangou Group, while the V Cavalry Corps and the IV Corps separated the Greek Trikoupis and Frangou Group. Trikoupis Group was effectively encircled. Trikoupis Group began its movement westwards on the morning of 29 August. Progressively and unexpectedly Greek units started running into the units of the Turkish V and IV Corps. Trikoupis ordered his 9th division to attack and break the Turkish line, in order to open the way to Dumlupınar. Quickly the Greek 9th division found itself attacking against superior Turkish forces (the 4th Corps) and fell into defense. The Turkish forces attacked also of the eastern flank of Trikoupis Group where the Greek 12th position was. Trikoupis progressively committed the 5th and 4th divisions in the defense of his Group, while keeping the 13th division in reserve. The battle lasted all day on 29 August, with heavy casualties on both sides. Trikoupis Group had been unable to open the way to Dumupinar or establish communication with Frangou Group. The Turkish forces had similarly been unable to destroy the Trikoupis Group, despite having encircled it with their II, IV, V and VI Corps. At 23:00 on 29 August, the badly battered Greek units of Trikoupis Group, disengaged and began marching towards Çalköy (), which was thought to be weakly held by Turkish forces. The Greek units had already lost much of their cohesion,