A few technical notes about eastern Vallo Alpino

Chapter I


The defensive systems

The circulars by the Ministry of War

Circular number 15000

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A typical clearing in Sneznik (m.Nevoso) area where it doesn't sound too unlike that any undeground cavity is chosen by bears as their den.

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The summit of Triglav (M.Tricorno, 2864 m) was cut by the old border between Italy and Jugoslavia. Triglav is the highest peak of Julian Alps and the highest point of the watershed between the Adriatic Sea and the Black Sea basin.

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Sneznik (Monte Nevoso, 1796 m) juts out from the sorrounding lower mountains (background at left). The peak was left in italian territory: an observation post was built few metres under the top (it has nowadays become a well known mountaineers hut).

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Another lovely pre-alpine mountain spoiled by fortifications, barbed wires, military trails and lodgements.

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A metal casamate embrasure lingers among the bush in a wonderful wood.

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Italian barracks are visible on the former italian side of Mount Lajnar, a powerful stronghold of eastern Vallo.



In spite of what can be read on the home page, the more i understand the Vallo, the more i realize how hard describing it may be. The argument is simply too wide: i will only talk about the defensive works built by Italy in the thirties, but, i won't even try to mention how the italian army was organized behind the lines. Don't you think anyway that i chose the easiest subjct: fortifications are only roughly similar to each others and it's not absolutely unlike that simple rules, which seem standard for the works described here, may be invalid for some others still to visit. 

I recall that my present document deals only with the fortifications built along the border between the Kingdom of Italy and that of Jugoslavia: these fortifications and what of them remains, lay in present Slovenia and Croatia.   Moreover, knowing  that a picture is worthy one thausand words, on the one hand i realize that the following notes could be somehow considered pleonastic, but  i also realize that, on the other hand, readers, along with pictures, had to be offered a proper comment and some explanations based on as far as i know of Vallo. The following notes are infact the result of my personal observations and some precise measurements taken in the field. Being my observation incomplete (defensive works of eastern Vallo are stimated to be more than 200), it is not unlike someone might note differencies visiting  fortifications simply not seen by me yet. Let these rough notes be considered just a kind of draft to be constantly kept updated and subject to corrections. By the way, whoever thinks to be useful by giving me hints or corrections, is warmly welcome to contact me.

Although incomplete, i hope that my website pics, commented by these notes, could anyway be usefull. Should a hiker, for instance, run into a bunker during an excursion, i hope to help him recognizing what he saw. Not only this, which might be the humblest case, but i have the presumption that my notes could be usefull also for those who have for long been studying other sectors of the wall and have never been given the opportunity to visit eastern Alps Vallo.

Moreover this seems a good occasion to thank some friends of mine   i've  for long been changing informations with either during bunker searching trips or by internet.

After these preliminary remarks, i will try here to give a general description of the fundamental elements which more or less clearly could be observed in these very modern (with regard to those times) fortifications. The task seems easily carried through if we deal with steel elements which are always the same. Nothing in general could be of course said about the overall disposition of the underground rooms and corridors although a precise range, within some standard dimensions fall, can be actually observed. These more or less standard dimensions are corridors broadness and height, square or circular section shafts and concrete walls thickness of some casamates.

The defensive systems

As it could be seen on some official plans of those times, the italian wall should have consisted of a series of fortifications built one close to the other in order to have a real impenetrable wall stretching along the border. As an example, one could cite the Adrian's wall or the chinese wall: in these examples a really continous wall had been built. In the case of Vallo alpino, the wall should have been made up by a continous series of modern fortifications which, according to official plans, should have been in a very tight connection.

I recall that the main aim of the wall was to prevent surprise action by the counterpart and to slow down as long as possible the enemy's advance in order for the defenders to organize a  mass counterattack action.

A defensive system is an organized line of fortifications and all the supporting logistical structures behind it. Defensive systems have different strenght according to the physical geography of the terrain on which the kind of enemy action depends. As the Alps themselves constitue a natural defense, the aim of the Vallo was just preventing the enemy to enter the plains through the valleys openings: fortifications were built either to block any road or track overcoming alpine passes or to protect strategically prominent summits along the border. To get this aim, it was thought that the Vallo should have been made up by as many as four defensive systems. Each of these four systems was indeed a double line since a rear parallel line was planned but rearly built. Although theoretilcally extablished, the third and the forth defensive systems also have rarely been built.

As for the strenght of each system, much depended on the geografical situation as already said. Italian seemed to have drawn a usefull teaching from what happened fifteen years before during the defeat of Caporetto battle when a bad distribution of troops and weapons between parallel lines caused the front breaking and the success of the austro-hungarian action. The strengh of each defensive system  must therefore depend on the particular geography of the front regardless of  being the first or the second line.

The first system had to be as close as possible to the border, while the second one had to be set at a proper distance from the first. The first system was often completed by simple observation posts built to spy enemy's movements, to detect and prevent surprise actions or to guide artillery shots. Many were crewed only in summer, while most of defensive works were manned all year around however hard the living might have been during the cold season.

Unfortunately for fascist Italy, the lack of financial resourses due to international enbargo, the redirection of steel towards the navy and the burst of the WWII prevented the regime to complete the wall and so most of works remained just on planning stage. Nevertheless, the main frame of the eastern wall has been built and was fully operative. Infact, observing a few original maps of certain sectors, the wall was actually a chain of fortifications protecting the most strategical places on the border. Therefore, it was not a continous system since only fortifications considered having top priority have actually been completed: particularly prominent summits were fortified and the fortifications which should have prevented attacks along either main or secondary roads crossing the border have been finished. These finished works were also fully operational. Many works were instead under construction when Italy inveded Jugoslavia in april 1941, but most of works were just planned. Among works planned by military commands, a little amount were planned by engineers and waiting for the works to begin; most were only ordered by the army but not even planned by engineers.

Whenever a circular was issued by the Ministry of the War in Rome, a new impulse to complete the wall seemed to pervade local military commands: not only were fortifications, planned by previuos circulars, carried out, but new ones would be taken in consideration.





AD 29 - VII EF

This inscription  witnesses that fortifications started before 30s.

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The main dwelling quarters underground room of a typical "200".


An example of "7000" position taken in Rijeka suburbs (courtesy of V.Tonic)

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Observatory opening of an 200 work (Courtesy of V.Tonic).

The inside of the small iron cupola with three embrasures which was used as observation post in most of "200". fortifications.


The circulars issued by the Ministry of War

Works on the Vallo Alpino began, on a large scale, in the early 1930s. During this time, some circulars were issued by the Ministry of the War in Rome to establish rules and technical procedures for building the fortifications on the Alps. So important the prescriptions of the circulars were, that defensive works complying with a certain circular are commonly referred to by the name of the circular itself.

During the 1920s, scattered work was already done on some Alpine sectors. Only a renewed fear of future invasions induced Rome to taking action. The result was that Circular number 200 was issued in January 1931: it was then that the Vallo Alpino defensive works began on a large scale all along the border with France, partially along the border with Swissland and Austria and, of course, along the border with the Reign of Jugoslavia. It was a complex project stretching from Tyrrenian shores to Adriatic sea and running all along the watershed of the entire Alpine ridge.

Isolated works on Julian Alps indeed started before 1931 but for sure all the works, eventually completed before circular 200, must have been modified to be compliant with this circular.
Circular 200 referred to the fortified positions as centers of resistance and each work was assigned a letter and number for identification. Later Circular 7000 became the basis for a new type of fortification simply known as a weapon position. The last important document was circular 15000 which was issued on 31st of December 1939. It was the basis for the largest and most modern works. It also began the last and more advanced type of fortifications building on the Alps.

Most of eastern Vallo works have been built according to circular 200 and they should be correctly referred to as centers of resistance, but, in general terms, any defensive work nowadays is simply called work (opera).
Circulars emissions started different phases of construction.

Phase I: 1931-1937. Ciruclar 200 set the standards for this period.
At that time, works on prominent summits and those blocking the lines of communciation were given top priority. The armament of these positions was the heavy machinegun and anti-tank guns. These defensive works had variable dimensions with different size garrisions. The ethiopian crisis, the expansionism of the strong ally of the new born Axis (anschluss of Austria) led Rome to understand the importance of enhancing the Vallo Alpino by new plans and designs.

Phase II: 1938- 1939. Circular 7000 was issued in 1938 when fortifications developed during the first phase were coming to completion. The defensive works built according to circolar 7000 were indeed smaller positions used to quickly strengthen the Vallo.
These positions are simply known as Pariani positions after the general who signed the circular. These small positions consisted of only a single block with two machine guns or an anti-tank gun sometimes without any underground rooms.

Phase III: From 1940 on. The last phase began when General R.Graziani issued Circular 15000 on December 31, 1939. This circular ordered some rules for more advanced and sophisticated positions. Anyway, by autumn of 1942 most work had stopped and just few of the multi-block Type 15.000 works were nearing completion.

Circular 15000

Circular 15.000 is important since it was issued after the invasion of Poland.
On those early phases of war, Mussolini had not yet committed Italy to joining his powerful Axis partner and this circular shows that Rome's primary intention was just defending her positions inside her alpine boundaries. Fearing that Italy would suffer a german invasion or annexation may have forced the regime to enhance the positions on the Alps.

This circular din't set any completely new standard for new types of defensive works. It is underlined the necessity to modernize the existing works, to start building the third and fourth defensive systems and a general classification of works is given with regard to the defensive systems on which they would have been built. The circular is written in so general terms that any local military command would have had the freedom to apply its general lines in different ways according to the  particular case.

The wall on eastern Alps was already full operative when circular 15000 was issued. This is why it seems difficult to find a real 15000 work built on these sectors. Moreover the circular says that the existing works, built according circular 200, should have been modified to become complying with the new circular."200 fortifications" were modified with elements of 15000 making the classification of the defensive works become very difficult.

The modernization followed three main lines: communications, logistical part reorganization and the weapons fire.

As for communications, "200 fortifications" should have been improved by some powerful domestical means of communication between the commander of the fortification and each position. Regardless of the lack of iron, observatories were to be built to improve the effectiveness of the fortification fire. I read some comments about communications written, in those times, by a powerful general (also author of following circulars): it was observed that "200 fortifications" fire was not very effective due to the lack of proper observatories whose importance was actually understimated. Each defensive work should have had at least one observatory by which the commmander would have been given the possibility to guide his fire. "200 fortifications", the general said, were like underground graveyards or submarines without periscopes. It was then noticed that, being commanders' observatories as important as weapons basements, they had to be as armoured as blocks were the same way that commanding decks on warships were as protected as guns turrets.

Circular 15000 set some generic rules about the mandatory presence of a larger and more complete logistical part.

Moreover, to improve the fire effectiveness, it was underlined the necessity to increase the number of combat blocks with frontal action in comparison to blocks with lateral or secondary fire action.

Within Circular 15000 there is a classification of the defensive systems with regard to the type of enemy attack.

Where the land is open wide or the alpine crossings are broader and lower, being the attack front wide, it could have been stopped only by the strongest defensive system (type A) which was supposed to be spread on a continuum of defensive works.

Where the Alps instead offer stronger natural defences, mountains and passes should have routed the attackers' action just along directions which could have been easily foreseen. It could have been sufficient for the defenders to only block these directions to stop the entire enemy action. This was the case of the type B defensive system which was supposed to properly stop columns of attacking tanks.

In particular cases, type C defensive system should have been adopted: the roads and the terrain are such that attacks can be only isolated, sporadic and following few and well known directions. Type C defensive system line is made up only by smaller fortifications, but strong enough to block the communications ways at particularly strategic spots. Type C defensive system would have required smaller fortifications since roads in this case were such not to allow the enemy important adancing by strong forces. The system was perhaps that used on narrow valleys inside mountanous areas where every communication is made difficult by the nature of the terrain itself.

The classification of the defensive works may be summed up this way:

1. Large.
These works had 5 or more weapon blocks which could include machine guns, anti-tank
guns, mortars and flame throwers. This fortification was commanded by an officer.

2. Medium.
They have from 2 to 4 combat blocks with weapons similar to larger ones. Unlike the larger
type, these fortifications might be commanded by a noncommissioned officer.

3. Small.
This type had only 1 or 2 blocks armed with a machine gun, anti-tank gun and sometimes a flame thrower. Because of its small size, the fort was to be occupied by the garrison only just before going into action against the enemy.

The classification of works is made regardless of the classification of the defensive systems: defensive systems could have been made up by any type of fortifications.

To Chapter II