a promise that the costs of improving his estate could be billed to the state. This was part of the bribery of senior Wehrmacht officers scheme. Kluge accepted the money. After severe criticism from his chief of staff, Henning von Tresckow, who upbraided him for corruption, he agreed to meet Carl Friedrich Goerdeler, an opponent of the Nazi regime, in November 1942. Kluge promised Goerdeler that he would arrest Hitler the next time he came to the Eastern Front. Then after receiving another "gift" from Hitler, he changed his mind and decided to remain loyal. Hitler, who seems to have heard that Kluge was dissatisfied with his leadership, regarded his "gifts" as entitling him to Kluge's total loyalty. For much of 1942 and early 1943, Army Group Centre was engaged in positional warfare around the Rzhev salient defending against Red Army offensives, collectively known as the Battles of Rzhev. The Soviet forces gained little ground for their losses, especially in the unsuccessful Operation Mars that commenced around the same time as Operation Uranus, the encirclement of the German forces in the Battle of Stalingrad. Kluge's forces were nevertheless depleted and early in 1943, he obtained authorisation to withdraw the 9th Army (General Walter Model) and elements of the 4th Army (General Gotthard Heinrici) from the salient. The resulting Operation Büffel saw the Wehrmacht abandon the salient in phases between 1 and 22 March 1943. The operation eliminated the Rzhev salient shortening the German lines by miles. The withdrawal was accompanied by a ruthless scorched-earth and security campaign, resulting in widespread destruction, razing of villages, deportation of the able-bodied population for slave labour, and killings of civilians by the troops of the Wehrmacht under the guise of "anti-partisan warfare". On 13 March 1943, Hitler authorised several offensives, including one against the Kursk salient. As the last Soviet resistance in the Third Battle of Kharkov petered out, Erich von Manstein, commander of Army Group South, attempted to persuade Kluge to immediately attack the Soviet Central Front, which was defending the northern face of the salient. Kluge refused, believing that his forces were too weak to launch such an attack. By mid-April, amid poor weather and with the German forces exhausted and in need of refitting, the offensives were postponed. On 15 April, Hitler and the OKH issued a new operational order, which called for the offensive codenamed Zitadelle ("Citadel"), to begin on