Vazovs Instructions on siege warfare
General Georgi Vazov was the Inspector of the Engineers and his Instructions were directed especially
to the pioneers, whose activities during the various stages of the siege were
carefully described with the aid of sketches showing the different kind of trenches
and field fortifications that they had to arrange. He paid little attention
to the action of the artillery, giving only brief indications about the role
that it had to play during the preparation and the progress of the attack.
This fact might explain why his lesson was poorly regarded by the artillery
officers before the outbreak of the war against
preliminary remarks about the different ways to conquer a fortress, Vazov
focused his attention on the gradual attack, describing the different stages
of the siege and the duties of the different heads of the troops involved in
the operation (the commander of the siege army, the chief of the general
staff, the heads of artillery and engineers, the directors of the telegraph
and railways units and the head of the sector of attack). The text was
innovative, being based on the lessons of the Russo-Japanese war and the
A fortress should be attacked only if it obstructed the progress of the military operations; otherwise it should be simply observed by a detachment. The best way to conquer a fortress was the siege or gradual attack, since abrupt assault was unsuitable with a great fortress, blockade was a waste of time, bombardment entailed a great consumption of ammunition and could be successfully employed only against a fort or a little fortress, and the accelerated attack could be launched only if the defender made some mistake. The siege of a fortress should be accurately planned and rapidly executed, since the raise of the siege had more disastrous consequences than not to start it at all. Especially the transport and the lines of communications should be accurately organized, since the movement of the siege park on common road was very difficult.
The siege army (detachment) should be composed by :
the army general staff with the chief of the artillery, the chief of the engineers and two staff officers for telegraph and railway troops respectively;
some infantry divisions, whose number was established according with the size of the fortress;
heavy field artillery : 3 batteries every infantry division;
artillery siege park, composed by 1/3 flat trajectory guns and 2/3 plunging firing howitzers;
pioneers : 2 companies attached to every division and 2 companies in every sector of the attacked front;
pioneer siege park with trench tools;
telegraph and telephone units;
railway troops with 1 construction and 1 exploitation company;
searchlight unit with two 60cm and 90cm searchlights attached to every division;
air unit with 2 kite and 1 spherical balloons, one for every sector of the siege;
the direction of the lines of communication.
Reconnaissance of the fortress. The first stage of the siege was the reconnaissance of the fortress, carried out by a cavalry force reinforced by 2 infantry battalions, 2 pioneer companies, 2 machine-guns detachments and 2 or 3 light howitzers batteries. Its task was to destroy the enemy communications and the waterworks; to seize the depots, the transports, the rolling stock and the main technical outfits; to find the enemy outposts and to collect information about the garrison, its armament and the defences of the fortress.
Advance of the siege army. The siege army approached the fortress advancing in one or more columns strictly connected one with another, in order to occupy the outposts that prevented it to move closer to the enemy and to deploy the siege artillery, beginning with the front chosen for the decisive attack. It could advance directly against the fortress only if it had all the means required for a successful attack : against an active enemy premature advance with field artillery only might cause the failure of the whole operation.
Encirclement (blockade) of the fortress. The fortress should be blockaded in order to prevent the garrison to be reinforced or supplied, to keep the residents to evacuate it, to cut its communications and to lock up the enemy within the limited range of its fortress artillery fire. An uninterrupted encirclement of the fortress entailed a great waste of troops that could not be concentrated in the point of the decisive attack. Therefore the siege army should occupy only the main junctions of the front outside of the range of the fortress artillery fire, watching the intervals between them with the cavalry. To avoid that the troops might be defeated in detail, the posts should be strongly fortified and firmly connected one with another and with the reserve. Enemy counter-attacks would be repulsed with the joint action of the reserve and the nearby troops. The blockade line should be fortified as soon as it was occupied and gradually reinforced in the aftermath with artificial hindrances, flanking strongpoint to avoid to be surrounded by the enemy, and rear positions to prepare counter-attacks. It was a matter of the highest importance to take care of the roads and of the line of communications, arranging optical signals and telegraph and telephone stations. To make easy the command, the blockade line could be subdivided in sectors with different heads.
Operations between the investment of the fortress and the arrival of the siege artillery. The commander of the siege army developed a detailed plan of action according with the information collected by the intelligence in peacetime and the results of the reconnaissance. For the decisive attack he chose the sector of the forts ring, whose fall would have the greatest importance for the fate of the fortress itself. In this stage of the siege, the means of transports, wood and all kind of materials were assembled in the places choose for the artillery and the engineer parks; railways, roads, bridges, tunnels etc. were built, improved or repaired; the outposts of the enemy were attacked to establish the line that infantry would occupy to protect the siege artillery. In these combats the troops could be effectively supported by the fire of the field howitzers and mortars. Infantry main positions the starting points for further attacks should be fortified on the basis of a plan prearranged by the head of the Engineers. The frame of the artillery positions should be constructed under the cover of the advance guards to be finalized and rapidly occupied as soon as the siege artillery arrived.
Artillery combat. The siege artillery was
Infantry combat. When the enemy artillery was forced to silence, almost in some sector of the forts ring, infantry suddenly jumped out and occupied the first firing position (first parallel line) that would serve as starting point for the following advances. Afterwards the troops moved further in the same manner, taking advantage of the pauses of the enemy fire and of the ground features, and reach the last firing position (last parallel line) that should be near the fort in order to open a close rifles and machine guns fire. Every new position was fortified with masked trenches connected with the rear by communication trenches out of the enemy sight and protected from enfilade fire. The front trenches were occupied by the chains of infantry, the back ones by the reserves.
Before the attack, the reconnaissance and the construction of the frame of the positions to be occupied were made by night, in strict silence, under the direction of the officers of the pioneers. After the first night the profile of the trenches should be height enough to protect a standing man. Before dawn the workers came back, the covering chains occupied the trenches that the following day were enlarged by another squad.
position (last parallel line) should be placed close to the forts ring, be
provided with a lot of exits, offer a good protection to the assault troops
and their equipment and be connected by telegraph and telephone with the head
of the sector, the head of artillery and the engineer park. The ground before
should be accurately reconnoitred by artillery and pioneer officers, who
examined the hindrances and the defences of the enemy (blockhouses,
observation posts, ditches, ramparts, gorges) to determine how they could be
demolished to facilitate the attack. The demolition and the clearance of the
hindrances was carried out methodically, opening passages 8-
Before launching the decisive assault, the field and siege batteries concentrated their fire at the fortifications that would be attacked in order to destroy the hindrances, the intermediate and flanking works and the dugouts, and to terrify the garrison. The forts were attacked both from the front and from the gorge; at the same time also the interval between the forts were attacked. The assault was launched suddenly, possibly on a wide front, starting from the last parallel line, as soon as the enemy was staggered enough and the fortifications were made almost inoffensive. The storm columns were composed by infantry, pioneers and sometimes also by heavy field artillery batteries; the reserves and the artillery stood back ready to advance.
The troops had been trained in advance; what needed for the assault (hand grenades, footbridges etc.) and the explosives had been amassed in the last parallel line the night before the attack. The storm troops reached their starting points by night, while the pioneers reconnoitred the ground for the last time, marking the way where the troops had to walk. The attack should start one hour before the sunset, so infantry could advance under cover of darkness, when artillery could not support the garrison with its fire. When a fort was captured, the pioneers inspected it to clean mines from the area. In the meantime the reserves occupied the last parallel line to be employed if the enemy launched a counter attack. When a fort could not be silenced or destroyed before the attack, it was necessary to resort to the slow methods of the mining warfare, tunnelling under no mans land and laying large quantities of explosives beneath the fort, to demolish the scarp and the works flanking the ditch.
When a sector of the defensive line was occupied, the troops should be rapidly redeployed in order to attack the inner defensive line or the core of the fortress without giving to the shocked and exhausted enemy the time for resting and reorganizing. This determination might cause the rapid fall of the fortress.
Duties of the head of artillery. The head of artillery was the assistant of the siege army commander as for the direction of the artillery units during the attack, and should fulfil his orders. He took care of the correct use of the field and siege artillery during the combat, of the timely supply of the ammunition and of the arrangement of the artillery park. Taking into account the results of the reconnaissance, he developed the plan for the deployment and the action of the siege batteries, for the disposition of the main and the intermediate artillery parks, for the arrangement of the communications between the units and with the rear and for the supply of ammunition. He asked for the air units, the searchlights and the technical troops he needed.