By the fall of 1938 North Moravia had approximately 250 heavy fortresses and 1195 smaller works. South Moravia had only 6 heavy fortresses and about 1000 smaller positions. West and South Bohemia had some 3993 pill-boxes and small-medium fortifications. North Bohemia had 1852 of the smaller works. Slovakia had 11 heavy and 1942 smaller fortifications.
Despite these numbers the much greater length of the Czech frontier mean that their defenses were much more thinly disposed than the French. In some sectors the depth of the French defenses was 11 km (6.8 miles), but the densest portion of the Czech fortifications was only some 5 km (3.1 miles) thick. In some area, especially in the South, the belt was only 100-150 meters (110-165 yards) thick!
The Germans conducted extensive tests after the occupation of the Sudetenland on the Czech forts, partly in hopes of gaining information that would be useable against the Maginot Line. The medium works proved somewhat vulnerable to artillery fire. The 88mm anti-aircraft gun could do major damage at 1000 meters while the 37mm anti-tank gun proved could destroy the machine-gun loophole at 450 meters distance.
One major drawback was that most of the works were constructed close to the German and Austrian borders, often within sight of border. This meant that the Germans could directly observe most of these and, more importantly, so could the Sudeten Germans who lived in the border areas. On one occasion some British officers were assessing the state of the defenses, but couldn't locate some until they inquired of a small Sudeten boy who proved to know exactly where everything was! This advance intelligence would have been very handy if the Nazis had actually attacked as Hitler wanted on October 1st.
A contemporary assessment by an Austrian general noted that the Czechs ignored a number of lessons learned by the K.u.K. (Austro-Hungarian) Army in the First World War. Among these were (1) The problem of defense of terrain between the bunkers at night. (2) The lack of interconnected bunkers such as proved effective in the Tyrol in 1915 and 1916. In many portions of the system bunkers were only connected by cables which could have been cut by the attacker. It was important for the defenders to be able to keep in touch with one another directly. (3) The absence of comfortable living quarters and adequate exits. By cutting off the electricity and sealing off the exits, the attacker could have made the defender's life intolerable within an matter of days. (4) The extensive use of reinforced rather than solid concrete. That contradicted experiences in Belgium and the Tyrol which showed that iron transmits shock more readily than solid concrete, which is also easier to repair.
Some of these points are arguable, but they do raise the question whether the Czechs erred by ignoring the engineering expertise of its officers who served in the K.u.K. Army when planning these fortifications by relying upon the French and their own home-grown men.
In the final analysis the conclusion must be that the defenses were incomplete and would not have prevented the Germans from conquering Czechoslovakia if she wasn't aided by her allies. Unquestionably the cost to the Germans would have been raised by the fortifications that were indeed complete, but most likely not enough to bleed them dry.
For a contemporary assessment.
For more detailed photos of some smaller Czech defensive works.
Comments and opinions are invited. Email me at sturmvogel@usa.net