'Sumpf' was a German unrealised plan to widen the salient to the west of Staraya Russa with an advance to the north by Generalfeldmarschall Ernst Busch’s 16^th Army in Generalfeldmarschall Georg von Küchler’s Heeresgruppe 'Nord' (November 1942).

The Soviet opposition was found by General Leytenant Pavel A. Kurochkin’s North-West Front in this sector, whose series of massive salients and re-entrants had been created by the northern flank portions of the Soviet army’s great 'Moscow Strategic Offensive Operation' of the winter of 1941/42, and maintained since that time by Hitler’s steadfast refusal to give up even the most dangerously exposed salients, which he regarded as launch points for offensives into the Soviet rear areas.