The failure of the Allies to capture Krithia or make any progress on the Cape Helles front, led General Ian Hamilton, commander of the Mediterranean Expeditionary Force (MEF) to pursue a new plan to secure the Sari Bair Range and capture the high ground of Hill 971 and Chunuk Bair. Both sides had been reinforced, with Hamilton's original five divisions increased to 15 divisions and the six original Ottoman divisions having grown to a force of 16 divisions. The British planned to land two fresh infantry divisions from IX Corps (Lieutenant-General Frederick Stopford), at Suvla, 5 miles (8.0 km) north of Anzac, followed by an advance on Sari Bair from the north-west to Hill 971.
At Anzac an offensive would be made against the Sari Bair range, by the New Zealand and Australian Division (Major-General Alexander Godley) on the northern flank advancing through rough and thinly defended terrain, north of the Anzac perimeter. The division had been reinforced with most of the 13th (Western) Division (Lieutenant-General F. C. Shaw), the 29th Indian Infantry Brigade and the Indian Mountain Artillery Brigade, to about 20,000 front-line infantry. The attack would be conducted by a Right Assaulting Column up Rhododendron Spur to Chunuk Bair and the Left Assaulting Column would divide at Aghyl Dere and half would advance across Damakjelik Spur and Azma Dere to the Abdul Rahman Spur and then attack Hill 971, the other part of the force would move to the right up Damakjelik Spur to Hill Q. To prevent delays, a Right Covering Force was to take Destroyer Hill, Table top, Old No 3 Post and Bauchop's Hill and the Left Covering Force was to reach Walden Point, cross Aghyl Dere and take Damakjelik Bair.
After the covering forces had captured their objectives by 10:30 p.m. the attacking columns would advance at 10:30 p.m. to reach the ridge an hour before dawn. Once Hill Q and Hill 971 had been captured, the Left Assaulting Column was to dig in and the Right Assaulting Column would consolidate Chunuk Bair and capture Battleship Hill, assisted by dawn attacks on the Nek and Baby 700 from the Nek from Russell's Top, by dismounted Australian light horse from the 3rd Light Horse Brigade, in concert with an attack on Chunuk Bair summit by New Zealanders from the New Zealand Infantry Brigade, who would traverse Rhododendron Spur, the Apex and the Farm. Hill 971 would be attacked by Gurkhas of the 29th Indian Brigade and Australians of the 4th Infantry Brigade.
The approach to the peak was made along Rhododendron Spur, which ran from the beach to the peak of Chunuk Bair. The Ottomans had outposts along the spur at the Table Top, Destroyer Hill and nearest the beach at Old No. 3 Outpost. There was also an Ottoman outpost on Bauchop's Hill to the north. All these outposts had to be cleared by the covering force, the four understrength regiments of the New Zealand Mounted Rifles Brigade, before the main assault column could proceed up the spur to the summit. The Auckland Mounted Rifles cleared Old No. 3 Outpost and the Wellington Mounted Rifles took Destroyer Hill and the Table Top. The Otago Mounted Rifles and Canterbury Mounted Rifles captured Bauchop's Hill, which was named after the Otago's commander, Lieutenant Colonel Arthur Bauchop who was killed during the attack. In all the New Zealanders lost about 100 men in clearing the outposts and while their efforts were successful, the plan was now running two hours behind schedule, making it difficult to reach the summit before first light.
The advance was initially made up the valleys, or deres, on either side of Rhododendron Spur and once past the Table Top, the New Zealanders climbed onto the ridge, leaving about 1,000 yards (910 m) to travel to the summit.
The three battalions travelling along the north side of the spur were in position by 4:30 am, shortly before dawn. They advanced to a knoll dubbed "The Apex" which was only about 500 yards (460 m) from the summit where at the time there were only a handful of Ottoman infantry. The Canterbury battalion on the south side of the spur was lost and delayed. Johnston made the fatal decision to wait for the last battalion to arrive before making the attack.
The attack on Chunuk Bair was a main element in a wider offensive. At 4:30 am a supporting attack was planned at the Nek against Baby 700, intended to coincide with the New Zealanders attacking from Chunuk Bair down onto the rear of the Ottoman trenches on Battleship Hill. The Battle of the Nek went ahead nonetheless, with tragic consequences.
The opportunity for a swift victory at Chunuk Bair had been lost. By 8:00 am the Ottomans had started firing on the New Zealanders on the spur. The commander of the Ottoman 9th Division, German Lieutenant-Colonel Hans Kannengiesser, had reached the summit and was preparing its defence. In daylight, after an exhausting climb and faced by stiffening opposition, the prospects for a New Zealand assault against the peak looked slim. Nevertheless, General Godley ordered Johnston to attack.
Two hundred yards beyond where the New Zealanders were positioned on the Apex was another knoll called "The Pinnacle" from which it was a straight climb to the summit. Off the side of the spur to the north was a small, sheltered plateau known as The Farm.
Johnston told the Auckland battalion to attack. About 100 made it as far as the Pinnacle where they desperately tried to dig in. Around 300 fell as casualties between there and the Apex. Johnston told the Wellington battalion to continue the attack. The battalion's commander, Lieutenant Colonel William Malone refused, stating that he was not willing to order his men to carry out a hopeless attack. He said his battalion would take Chunuk Bair at night.
During the day the New Zealanders were reinforced by two battalions from the British 13th (Western) Division; the 7th Battalion of The Gloucestershire Regiment and the pioneers of 8th Battalion, the Welch Regiment.
Shortly after 3:00 am on 8 August, following a naval bombardment of the peak, the Wellingtons, followed by the Gloucesters, reached Chunuk Bair virtually unopposed. The preceding barrage had driven most of the Ottoman defenders away as the ground was too hard and rocky for deep entrenchments.
Chunuk Bair was hard to defend, it was only possible to scrape shallow trenches amongst the rocks and the peak was exposed to fire from the main Ottoman line on Battleship Hill to the south and from Hill Q to the north. If the original plan for the offensive had worked, Hill Q would have been in Allied hands. Allanson's battalion of Gurkhas reached it briefly the following day but were in no position to offer relief to the troops on Chunuk Bair.
By 5:00 am, the Ottomans counter-attacked the Wellingtonians. The slope of the hill was so steep that the Ottomans could get within 22 yards (20 m) of the trenches without being seen. The New Zealanders fought desperately to hold off the Ottomans, firing their rifles and those of their fallen companions until the wood of the stock was too hot to touch. When the Ottomans got up to the trenches the fighting continued with the bayonet. The Ottomans overran part of the New Zealand trench and took some prisoners. In full daylight, reinforcements were only reaching the summit at a trickle.
The fight raged all day until the trenches were clogged with the New Zealand dead. Around 5:00 pm, Malone was killed by a misdirected artillery shell, fired from either Anzac or a British ship.
The Ottomans had reclaimed the east side of the summit and were reinforced by the arrival of the 8th Division from Helles. As the extent of the Allied offensive became apparent, General Otto Liman von Sanders, the commander of the Ottoman forces in the Dardanelles, appointed his competent officer, Colonel Mustafa Kemal, the commander for the defence of Suvla and Sari Bair.
As darkness fell on the evening of 8 August, the fighting subsided and the Wellington Battalion was relieved. Out of the 760 men of the battalion who had reached the summit, 711 had become casualties. Whereas Malone had resisted sending his men on a suicidal charge when told to follow the Auckland Battalion on 7 August, a day later the outcome would be the same. The New Army battalions had suffered the same. 417 casualties amongst the Welch pioneers and 350 amongst the Gloucester's including all the officers of the battalion. For the wounded the suffering was only beginning. Some took three days to travel from the higher reaches of Rhododendron Spur to the beach, a little over a kilometre away.
Godley remained at his headquarters near the beach, largely ignorant of the state of the fighting. His plan for 9 August was to take Hill Q. The main force for the assault was a brigade commanded by Brigadier General Anthony Baldwin. Baldwin commanded the 38th Brigade of the 13th Division but the situation was so confused that the force he led towards Hill Q contained only one of his normal battalions, the 6th East Lancashires. He also had the 9th Worcestershires and 9th Warwicks from the 39th Brigade and the 5th Wiltshires from the 40th Brigade (who would later be redirected to reinforce Chunuk Bair). Plus he led two 10th (Irish) Division battalions; the 10th Hampshires and 6th Royal Irish Rifles from the 29th Brigade. Most of the 10th Division had landed at Suvla on 7 August.
This force would climb to Hill Q from the Farm. At the same time the New Zealanders on the right from Chunuk Bair and units of General Herbert Cox's Indian Brigade on the left would also attack the hill. The plan failed when Baldwin's battalions became lost in the dark trying to find the Farm which they did not reach until after dawn, around 6:00 a.m. The only force to reach Hill Q was Allanson's battalion of Gurkhas. They suffered the same fate as Colonel Malone, shelled by their own artillery, and their stay on the hill was brief.
With the offensive once again stalled, the New Zealanders on Chunuk Bair had to endure another day of Ottoman harassment. As night fell the remaining New Zealanders moved back to the Apex and were replaced by two New Army battalions, the 6th Battalion of The Loyal North Lancashire Regiment and some of the 5th Battalion of the Wiltshire Regiment from Baldwin's force.
On the morning of 10 August Mustafa Kemal led an overwhelming Ottoman counter-attack. If Chunuk Bair, the one Allied success of the August offensive, was recaptured, the battle was effectively over. His plan lacked subtlety but was brutally effective - overrun the defenders by sheer weight of numbers. Mustafa Kemal had stopped the advance of IX Corps at Suvla, with a counter-attack at dawn on 9 August and late in the day reconnoitred Chunuk Bair and planned an attack with six battalions.
There were about 2,000 defenders on or below the summit of Chunuk Bair. Baldwin's brigade at the Farm numbered a further 3,000. The Ottomans swept over the Lancashire battalion on the summit, few of whom survived (510 men were reported missing). The Wiltshires were unarmed and un-equipped and were scattered everywhere. On the right flank, the Ottomans captured the Pinnacle, driving the New Army troops before them. New Zealand machine gunners positioned at the Apex shot down the Ottomans as they tried to continue down the spur. The gunners could not discriminate friend from foe and killed many New Army troops who were amongst the charging Ottomans, as the Leinsters were rushed up to the Apex to reinforce. At the north side of Rhododendron Spur, the Ottomans descended from Chunuk Bair to the small plateau of the Farm and overran Baldwin's brigade, the Warwicks being almost annihilated, the 6th Royal Irish Rifles losing half its number and Baldwin being killed; the survivors retreating to Cheshire Ridge. The Turkish infantry were exhausted and fell back to the main ridge and the Farm plateau became part of no man's land.
The loss of Chunuk Bair marked the end of the Battle of Sari Bair. Fighting would continue elsewhere until 21 August but there would be no more attempts to capture the heights. The Apex formed the new front line on Rhododendron Spur. In 1919 burial teams found the Farm still covered in the bones of the men from Baldwin's brigade, who were interred in The Farm Commonwealth War Graves Commission Cemetery when it was constructed on the site after the Armistice.
Charles Bean, the Australian official historian wrote that the Ottomans had 9,200 casualties in four days at Chunuk Bair and Hill 971, from 1,800–2,000 on the 19th Division sector around Baby 700 and the top of Monash Valley and 6,930 losses in the 16th Division, mainly at Lone Pine. The total of Ottoman casualties at Anzac was about 18,000 men and British casualties were 12,000–13,000 men.
A memorial arch, the Malone Memorial Gate, commemorating Lieutenant-Colonel Malone was constructed in Stratford, New Zealand in 1923 and a plaque unveiled in the New Zealand Parliament's Grand Hall in 2005.
One Victoria Cross was awarded for actions at Chunuk Bair to Corporal Cyril Bassett, who repaired phone lines while under fire.
New Zealand writer Maurice Shadbolt produced a play Once on Chunuk Bair in 1982. A film version Chunuk Bair (Daybreak Pictures) was released in 1991. There is a detailed fictional description of the battle from the point of view of an Ottoman Turkish soldier in Birds Without Wings by Louis de Bernieres, author of Captain Corelli's Mandolin.
Musician PJ Harvey sings about the aftermath of this battle in the song "On Battleship Hill" from her 2011 album Let England Shake.