A major confrontation in the First World War, following which the German-Austro-Hungarian offensive aimed at penetrating Moldova and removing Romania from the war was stopped.

Almost at the same time as the offensive from Transylvania, the Oituz, Kassin and Slanic valleys, the Germans attempted to break the front through southern Moldova, on the Focsani-Mărăşeşti direction, the two operations being closely related. The mission of Oituz was entrusted to the Gender-Driven Group. Friedrich von Gerock, who was located in the right flank of the Austro-Hungarian Army, deployed in the Eastern Carpathians. Displaced between the Doftana Valley and Ireşti, it consisted of the 8th Army Corps (composed of 70 Honved Divisions, 117 German Infantry and 71 Austro-Hungarian Infantry) and the Haber Group, which consisted of the 8th Austrian-Hungarian Mountains Brigade, Division 1 Austro-Hungarian cavalry, the 37th Honvez Division, etc.

According to the plan, the main strike was on Ferestrău-Grozeşti-Onşti (Valea Oituzului), while the 70th Honved Division attacked Târgu Ocna to destabilize the right flank of the Romanian Army 2 and the left flank of the Russian Army 9. The disproportion of forces was quite large, to the detriment of the Romanians. Thus, if the enemy had 54 battalions and 200 fireplaces, the Romanian army had 34 battalions and 104 fireplaces. At the same time, the Romanian Army had to cover the breach left by the departure of the Russian Army Corps 40 in Galicia and Bucovina, where on 19 July / 1 August 1917 the Russian front was pierced by Austro-Hungarians and Germans. In compensation, he recaptured the two divisions, 7 and 12, which had been taken to strengthen Army 1, which was preparing the offensive from the Namoloasa sector. The entire Army 2 device was 60 km wide, the main sectors being driven by gender. Gheorghe Văleanu and Gen. Arthur Văitoianu. The battle began on July 26 / August 8 (two days after Marasesti) with a few hours' bombing, followed by the 8th Corps attack, the shock being received by the 6th and 7th Romanian divisions forced to withdraw. In the following days the enemy occupied important positions such as Cireşoaia peak, the Coşna hills (789 m) and Ştibor. As a dangerous situation had arisen, the Great General Headquarters strengthened the 2nd Army with the 1st Cavalry Division, the 1st Hunting Regiment, the Mountain Hunting Battalion, and the Border Guard Brigade. The 1st Cavalry Division attacked Stibor Hill, conquering the 629 line alignment (Boboc Grass), and the 1st Hunting Regiment hired violent fights around Grozesti. On July 31 / August 13, a Romanian counterattack aimed to successfully retake the Coşnei, and Cireşoaia peak, failed. The Battle of Oituz took place on July 29 / August 11 - July 31 / August 13, when the enemy made great efforts to overcome the concentration of Romanian troops. Animated by the slogan "This is not over!", The Romanian soldiers resisted with heroism, frustrating the opponents' plans. Until Aug. 5/18, battles decreased in intensity, limiting to artillery duels and patrol clashes. On August 6/19, the Gerock group resumed the offensive, managing to reoccupy Coşna, but without any further succes.After August 9/22, the calamity gradually settled, the enemy being exhausted by the efforts made. The losses of the 2nd Army in the Battle of Oituz were significant, amounting to 12 350 soldiers, including 1 800 dead, 4 850 wounded and 1 570 missing. By the victory of Oituz, the plans of Germany and its allies to bring Romania out of war and penetrate Russia's Ukrainian part were thwarted, and the existence of the Romanian state was defended. At the same time, the morale of the population remained high, still hoping for a favorable outcome to the war. However, following the events in Russia and the coming of power to the Bolsheviks (October 25 / November 7, 1917), Romania's ally on the Eastern Front ended separate peace with the Central Powers in mid-December 1917, forcing Romania to end the armistice Focsani (November 26 / December 9, 1917). Famous figures were involved in these battles. In the Battle of Oituz was the Corporal Constantin Musat, who had lost an arm during the fighting, refused to be left in the fire. He argued that as long as he had an arm he could throw out grenades. On August 13, 1917, during a German attack, when the Romanian lines were in serious danger, our hero remained in position to continue to defend the front. His last words, before being killed by a bullet, were: "Grenades boys, grenades." German general Erwin Rommel, dubbed the "Fox of the Desert" in the Second World War, was also seriously injured in his hand in August 1917 in the battles for the conquest of Oşszów Mountain. This is why it is often said that Rommel learned what war is on the Romanian soil.