night fighting with even fewer successes. The Luftwaffe also contributed fighter cover for U-boats venturing out into and returning from the Atlantic, and for returning blockade runners. Development of night fighting Although night fighting had been undertaken in embryonic form in World War I, the German night fighter force, the Nachtjagd, had to virtually start from scratch when British bombers began to attack targets in Germany in strength from 1940 as far as tactics were concerned. A chain of radar stations was established all across the Reich territory from Norway to the border with Switzerland known as the "Kammhuber Line", named after Generalleutnant Josef Kammhuber, and nearby night fighter wings, Nachtjagdgeschwader (NJG), were alerted to the presence of the enemy. These wings were equipped mostly with Messerschmitt Bf 110 and Junkers Ju 88 aircraft, which would later be outfitted with the Lichtenstein nose-mounted radar. The Messerschmitt Bf 110 was the most successful night fighter that served in the Luftwaffe. Among the most notable night fighter aces were Helmut Lent, who shot down 110 enemy aircraft and Heinz-Wolfgang Schnaufer, who shot down 121 enemy aircraft. Lent mostly flew in the Bf 110 (and variants of the Ju 88), while Schnaufer flew the Bf 110 exclusively. The Bf 110's main strength was its ability to carry heavy armament in its nose section. The later G series was fitted with 20 mm MG FF/M cannons and sometimes with two 30 mm MK 108 cannons. Starting in Mid'1944 the Bf 110 G-4 night fighters entered serial production with two MG FF/M as the Schräge Musik 'off-bore gun' (upward firing) system for attacking Allied bombers from underneath with several units field modifying their Bf 110 with this system some time earlier. The Schräge Musik cannons were typically mounted in the rearmost glazed area of the cockpit in the Bf 110 or in the fuselage behind the cockpit on other machines. Several Dornier Do 217, Junkers Ju 88 and Heinkel He 219 carried similar installations. To compound the British night bomber problems the Avro Lancaster, Handley Page Halifax and Short Stirling did not carry ventral ball turrets under their fuselage, making them vulnerable to this kind of attack. During the 1942–43 timeframe, the formerly all-black night fighter camouflage used by Luftwaffe night fighters had yielded to a light-color camouflage scheme that took advantage of the skyglow over German cities at night — this generally comprised the