The 'KW-Ligne' was the Belgian primary defence line, more fully known as the 'Koningshooikt-Wavre Ligne', against a possible German armoured invasion through the centre of Belgium (September 1939/May 1940).

This defence line was also known as the 'Dijle-Ligne' (Dyle Line) after the river of that name, and its construction was ordered by the Belgian war ministry. The line’s defences were built between September 1939 and May 1940 as a series of bunkers and barricades between the village of Koningshooikt and the city of Wavre. The barricades had four constituents, namely Cointet elements designed by a French colonel, Léon-Edmond de Cointet de Fillain, and comprising heavy steel fence segments about 9 ft 10 in (3 m) wide and 6 ft 7 in (2 m) high, typically mounted on concrete rollers and connected to each other by steel cables; railway tracks drilled partly into swampy areas; concrete ditches filled with water; and other steel constructions designed to hold off the attacks of armoured vehicles.