 Pari gbolohun yii: Ni ọdun 1950 Koch di Repetitor fun ballet, opera ati operetta ati 2nd Kapellmeister ni Meiningen, nibiti o ti ni igbega lati igba naa lọ nipasẹ oludari ile iṣere Fritz Diez. Iṣẹ tó gbájú mọ jù lọ nínú iṣẹ rẹ ni pé ó máa ń darí orin opera. Láti ọdún 1955 sí 1958 ó jẹ 1st Kapellmeister ní ilé orin Opernhaus Halle. Nibẹ, ni ọdun 1958, o ṣe agbejade ballet Kreuzbauer Ulrike nipasẹ Carl-Heinz Dieckmann, ti Henn Haas kọwe ati ṣeto lakoko Ipolongo Jẹmánì ti ọdun 1813 si iṣafihan akọkọ. Ní ọdún 1958, ó lọ sí Ilé-ìṣeré Stralsund gẹgẹ bí olùdarí orin. Lati Halle, o mu oluranlọwọ oludari rẹ Harry Kupfer, ti o jẹ bayi oludari ile-iṣere orin nikan lati ṣe awọn opera wọnyi fun u ni Stralsund: Der Freischütz nipasẹ Carl Maria von Weber, Enoch Arden nipasẹ Ottmar Gerster ati The Merry Wives of Windsor nipasẹ Otto Nicolai. Ní ọdún 196061, ó lọ sí Stendal gẹgẹ bí olùdarí orin. Ní ọdún 1961, ó mọ pé : Aṣikiri ọmọ Hungary Béla Hollai ni Göttingen ti Iwọ-oorun Germany, iṣẹ apapọ laarin Göttinger Symphonie Orchester ati Stendal pẹlu awọn iṣẹ nipasẹ Josef Suk, Aram Khachaturian, Carl Maria von Weber ati Robert Schumann. 