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The north: Afsluitdijk


The German 1st Cavalry Division [later in 1940 reformed to the 24th Tank Division] had taken the last defences in front of the Afsluitdijk on the 12th and subsequently prepared for an assault on the most challenging target of all: the formidable complex of heavy and medium size casemates at the sluice complex close to the eastern extremity of the Afsluitdijk. This fortified complex was called Kornwerderzand [after a hamlet nearby the causeway] and was in essence formed by two lines of casemates.

The taking of the Kornwerderzand fortress was much easier said than done. It was a modern fortification that was situated about 4 km offshore mainland, which made the approach a massive challenge. The only way to approach the fortress over land would be along the narrow causeway. The fortress was also prepared for a naval assault, with gun and machinegun positions in directions to repel such an effort. Yet the Germans were not planning a maritime raid and were convinced that a battery of 8,8 cm Flak guns and bold boots on the ground would do the trick. But would it?

The Kornwerderzand Fortress

The Fortress was positioned at the eastern sluice and barrage complex in the Afsluitdijk. These water-works were in use to have the sweet water of the Ysselmeer mix with salty water of the Wadden-sea and to be able to lock shipping in and out of the Ysselmeer. Near the sluice complex the causeway was much wider than elsewhere and the quite extended water-works island had been designed from the start to also hold heavy fortification constructions. When the enclosure dike had been constructed in the 1930's the War Department had demanded from the start the construction of heavy fortifications on both extremeties of the 30 km long dike, aware as they were that it presented an access-road to the northwestern part of the country for an invader coming from the east, e.g. Germany. Heavy bunkers were constructed on the main structure and on jetties at the entrances of the sluice. On the east side of the complex was the front line of comprising several casemates, on the rear (west) side was a second line of defences.

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Aerial photograph of the Kornwerderzand fortress and sluices (may 1940)

The forward bunkers were meant for defences eastwards and to both sea sides. The western line [just behind the first] for enemy threats from the rear. Altogether 17 casemates had been built. All of these casemates were designed such that they were able to withstand considerable impact of 21 cm rounds [indirect fire] and even the occasional 28 cm round [indirect fire]. The ceiling and walls of the main structures were made of 3 m thick reinforced concrete. The approach had been mined on both sides of the causeway and a road-barricade was set a few hundred yards in front of the complex. Two strong search lights were able to project (indirect) illumination on the approaches, sothat even during night hours the barricade and the causeway itself could be lit. On either side of the Fortress - the sea sides - MG casemates had been constructed, which could prevent small amphibious landings.

The casemate-complex provided shelter to 230 men, 21 heavy machine guns Schwarzlose [7.9 mm], three modern casemate guns and a navy gun [open position] of 5 cm. An identical casemate complex had been built at the west end of the Afsluitdijk, at Den Oever.

These complexes had been constructed and paid for by the Ministry of Transport, Public Works and Water Management in the thirties. This was a result of the complaints that the military had filed after the plans for the construction of the Afsluitdijk [30 kilometres length] had been revealed [construction started in 1931]. The connection between the north-eastern and north-western provinces would be a liability to the national defence system, because by its construction an invader was presented an alternative route towards the west. As a result of these complaints the civil authorities had incorporated the construction of the two fortifications in their specification.

In May 1940 a small detachment [taken from the Wons line, of 12th Border Infantry Company] had been stationed halfway the dike [at Breezanddijk - a small harbour facility]. This unit, comprising two infantry platoons [70 men], three light navy guns and two heavy machineguns, was dedicated to prevent German amphibious landings on the dike beyond the direct vision of both fortresses. They did however face the challenge of relatively vulnerable positions, because no casemates had been constructed at this position. Only a couple of houses, a small pub and a civil servant building provided for some shelter, but obviously these average civil buildings were not at all bomb-resistant.

The battle for the Afsluitdijk

For one reason or the other the Germans had found out about the presence of the two isolated platoons at Breezanddijk. In the morning of the 12th six or seven fighters [probably of II/TrGr186, a group of fighters meant to be stationed on board of the German carrier "Graf Zeppelin" that would never be actually commissioned] suddenly dove down from the sky and strafed the troops and houses. The sad result being two civilian deaths and one soldier killed. Ten more got wounded. After this event had been reported to the commander of the Fortress Den Helder, the unit was called back. At the 13th no troops were present halfway the Afsluitdijk anymore. Fortunately the Germans had cancelled their planned maritime operations [the requisitioning of ships failed as we have seen before] due to lack of shipping and the clear presence of Dutch navy forces.

Still in the evening of the 12th the Germans had sent an insignificant patrol onto the dike fortress. Maybe they thought that the Dutch defenders had run off with the occupation of the Wonsline, but that was a huge miscalculation. The commander of the fortress was an esteemed and highly recognised officer, Captain Boers [he would join the resistance movement during the occupation of Holland, and was executed by the Germans in the concentration camp Oranienburg in 1942]. He was a professional officer and was considered a born leader. His men trusted their lives to this man and would follow him into the blind. Furthermore, their confidence was boosted by the formidable defences. These men would not give way, not under any circumstances. The German patrol approached the fortress along the narrow causeway. When they were very close to the first casemate line and after they had tried to extinguish one of the search lights [hidden in one of the casemates] one Dutch machinegun opened fire and pinned them down. Some of the Germans boldly tried to crawl forward, but their lives ended in the minefield just ahead of the barricades. Two of them were torn apart; the third one lived and retired to his unit.

During the night three 2 cm Oerlikon anti-air guns and 4 heavy AA machineguns arrived at Kornwerderzand. The troops quickly built improvised coverage around the three 2 cm guns [during the night], which had been positioned on top of three of the bigger casemates. The machineguns were installed in the second line. Then the defences had even some moderate anti-air defences - a rare thing in the Dutch army of those days.

The German plan of attack was pretty straight forward. First a number of Luftwaffe strikes would be launched against the fortress. Next an extended artillery bombardment with howitzers would be laid in front of the casemates [in order to clear up the minefields and the barbed wire barricades], after which 88-guns [the notorious German 8,8 cm guns] would pound the casemates making use of their flat projectile trajectory. After this ordeal a full battalion would advance to clear up the remaining resistance, if any ...

At around 0430 the first German planes passed over the heads of the fortress defenders. Much to the surprise of the pilots [the previous three days no air defences had bothered them] they were suddenly shot at by 20 mm guns and one of the two planes [Ju-88] dashed into the sea. After this first reconnaissance a full squadron Ju-88 followed and started strafing the AAA crews. The crews stayed where they were and only after the logistics [of new ammunition] failed they took cover. Soon after, the German planes disappeared. Not much later they returned and again a cat and mouse game between them and the gun crews unfolded. Hereafter four more air strikes followed. In total 62 planes (!) in five waves. Only two gun crew members suffered wounds, but none so bad that they needed to retire. The attackers lost three more planes [all Ju-88] that all ditched into the sea.

It was well after 1700 hours when the German guns finally opened fire. Soon the first casemate line was covered in smoke and dust. Some German projectiles hit the armoured plates in front of the embrasures, some even penetrated the closed armour-plates. No casualties were suffered, but of one of the three 5 cm guns the aiming device got damaged beyond repair. It was symptomatic for the moral of the men that during the shelling tea was served as if nothing was happening! The commander did however fear for the fate of the precious AAA guns and ordered a squad to dismantle them and bring them inside. Two of the three guns were safely retrieved from the top, but the third gun had been destroyed by a direct hit shortly after the first two had just been salvaged.

At 1800 hours, after one full hour of artillery bombardment, General Feldt gave the order to advance. One company took point and its first platoon moved the entire four clicks down the causeway, where the balance of the battalion stayed in the dead angle of the dike. The howitzers continued their shelling of the Dutch positions until the platoon of stormtroopers had almost reached the first barricade. Captain Boers had observed the Germans through his powerful periscope and instructed his battery and machinegun commanders to hold fire until his order "fire at will". The captain, much aware of the German vulnerability on the narrow and open causeway, let them approach to about 800 metre in front of the line. He then ordered only one of the main casemates to open fire. The machinegun and casemate-gun fire forced the Germans to disperse over the dike. This was the moment to order another casemate - on the other slope of the dike - to open fire. The attackers were then caught in a deadly cross fire and all they could do was stay low and stay put. At 1920 hours the captain ordered his crews to cease fire. An unrealistic silence fell over the dike, when also the German artillery stopped firing. The Germans waited until darkness to start crawling back. The assault had failed completely.

During the night the captain saw to it that the dike was illuminated on a frequent basis. One time by means of one of the search lights, the other time by means of flares. Incidentally he ordered some machinegun bursts over the dike surface. This way he prevented the Germans from undertaking a stealthy action under the cover of darkness. The Germans however had no plans to attack the fortress again this day. They realised that the casemate complex and its favourable position were far too strong to take as long as no specialised heavy artillery would become available from Germany. And this special material would not be mobilised. The dike defences had withheld the German attack, and did so by only applying the fire power of two of its casemates. It was a boost for the moral.


The Dutch had only two men wounded and suffered no KIA. About the number of German casualties suffered during the main assault many phantom stories roar. Shortly after the May War rumours spread that it must have been in the hundreds. Truck-loads of bodies would have left the Afsluitdijk. Quod non.

In reality German loss-records, which are quite reliable for that era, contain only seven men killed or mortally wounded in action as a consequence of the Afsluitdijk raid. The count of only seven dead seems hard to believe for some, but the Dutch accounts of hundreds of dead and wounded are much exaggerated.

As far as body-counts matter, the Germans were defeated at this particular location in the north of the country and that this achievement was fairly insignificant on the total picture of a lost war [at that stage] did not matter to the proud defenders. They had stood ground against the invincible German army and rightly they - the 225 men of the Kornwerderzand fortress - took pride in that achievement.