After the First World War, there was a desire to better defend the Netherlands. Certainly when the rearmament of Germany under the Nazi regime presented itself, work began on the construction of the Defense Canal, part of the Peel-Raamstelling, which was partly constructed as a job creation project.
Since the Defense Canal was very far to the east, they wanted to build an extra tank ditch a little further west to slow down an attack, should the line at the Defense Canal be breached. This became the Choral Canal, named after the chord cut off from a circle. Several minefields were also built near the Koordekanaal. However, hardly any money was provided for the construction of this line and, unlike the Defense Canal, no bunkers were built here.
When the Germans invaded on May 10, 1940, there were too few soldiers to adequately man the Koordekanaal. The few soldiers stationed there withdrew after three days. In doing so, they blew up the bridges over the canal, which would create an obstacle for the Dutch soldiers who later had to withdraw from the line at the Defense Canal. The civilians who stayed in this area were also unnecessarily endangered.