From 1 April 1881 to 31 March 1887 he was posted as battalion and regimental adjutant to Infantry Regiment No. 132 in Glatz. On 1 April 1887 he was seconded to the General Staff to Berlin. After a number of regimental and staff assignments Kosch was promoted to
Oberst on 22 April 1905 and took command of the Landwehrbezirk II in Berlin. On 16 February 1907 he took command of the 8. Brandenburgisches Infanterie-Regiment „General-Feldmarschall Prinz Friedrich Karl von Preußen“ Nr. 64 in
Prenzlau. On 19 August 1909 he was promoted to
Generalmajor and assigned to the 78th Infantry Brigade in
Brieg. On 22 April 1912 he was made Generalleutnant and he was appointed commander of the
10th Division in
Posen. After the outbreak of World War I he led his division into the
Loraine region on the
Western Front. On 9 October 1914, he became commander of the
I. Army Corps in Lithuania, where his troops opposed numerically superior Russian forces. After initial tactical setbacks Kosch and his men finally won the
Second Battle of the Masurian Lakes. For this victory Kosch was awarded the
Pour le Mérite. On 11 June 1915 he was appointed
Commanding General of the
X. Reserve Corps. He led them in the battles on the
Dniester, the
Battle of Gnila Lipa and at Krasnostaw. He transferred to the
Balkans Theater, where he fought against Serbia. For his success Kosch received, on 27 November 1915, the Oak Leaves to his Pour le Mérite. At the end of February 1916 the
Battle of Verdun began, and Kosch was in it. He was promoted to
General der Infanterie on 18 August 1916. Ten days later he assumed command of the newly formed
General Command No. 52, a.k.a. the Danube Army; that was used in the Bulgarian Danube region. The
multi-day battle at Argesch, in late November to early December 1916, culminating in a Romanian defeat, led to the occupation of
Bucharest and the crumbling of Romania's western and northwestern front sectors. From 1 May 1917 on he temporarily led the
9th Army until the arrival of
Johannes von Eben. After dissolution of the Danube Army in March 1918 Kosch participated in the occupation of Ukraine and the struggles against the
Red Army. On 1 May 1918 he was appointed commander of all troops in Taurida and the Crimea. Directly after the war he commanded the
Border Guard East, effectively all German forces east of Berlin, before he retired from the Army on 10 January 1919. Kosch died in 1942 and was buried in the
Invalids' Cemetery. His grave did not survive. == Awards and decorations ==