Chapter VI: The battle plan (continued)

Surprise has been, from time immemorial, one of the most potent weapons in the armoury of the tactician. It can be achieved not merely by doing that which the enemy least anticipates, but also by acting at a time when he least expects any action. It was a weapon which had been employed only rarely in the previous greater battles of this war. The offensive before Cambrai, planned by General Sir Julian Byng, and the battle of Hamel, were rare exceptions to our general procedure of heralding the approach of an offensive by feverish and obvious activity on our part, and by a long sustained preliminary bombardment of the enemy's defences, designed to destroy his works and impair his _moral_.

The situation on the Fourth Army front, early in August, 1918, offered a rare opportunity for the employment of surprise tactics on the boldest scale. The incessant "nibbling" activities of the Australian troops during the preceding three months had been of such a consistent nature as to suggest that our resources were not equal to any greater effort upon such an extended front as we were then holding, from the Ancre down to and beyond Villers-Bretonneux. On the other hand, the passivity of the first French Army, to the south of the latter town, conveyed no suggestion of any offensive enterprise on the part of our Ally in this region.

The problem, therefore, was to convert an extensive front from a state of passive defence to a state of complete preparedness for an attack on the largest scale, and to keep the enemy--who, as always, was alert and observant both from the ground and from the air--in complete ignorance of every portion of these extensive preparations, until the very moment when the battle was to burst upon him. It was, of course, a question not merely of deceiving the enemy troops in their trenches immediately opposed to us, but also of arousing in the minds of the German High Command no suspicions which might have prompted them to hold in a state of readiness, or to put into motion towards the threatened zone, any of the reserve Divisions forming part of their still considerable resources.

The following memorandum, which was issued to the whole of the senior commanders in the Australian Corps on August 1st, gives in outline some of the measures adopted to this end:

"SECRECY.

"1. The first essential to success is the maintenance of secrecy. The means to be adopted are as follows:

(i) No person is to be told or informed in any part or way until
such time as the development of the plan demands action from him.
This is the main principle and will be pursued throughout, down to
the lowest formation.

(ii) Divisional Commanders will work out their reliefs in such a
way as will ensure that the troops in the line know nothing of
the proposed operation until the last possible moment. This will
apply in particular to any troops who may be employed in the area
south of the AMIENS--VILLERS-BRETONNEUX railway.

"2. In order to conceal the intention to carry out a large operation on this front the following plan has been adopted:

"The Australian Corps has been relieved of one divisional sector by the Third Corps, and takes over a divisional sector from the French Corps. The object of this is to lead the enemy, and our own people, too, to believe that the action of the French in the SOISSONS salient has been so costly as to demand that further French troops had to be made available, and that this is the apparent cause of the extension of the Australian Corps front to the south.

"3. (a) The idea is being circulated that the Canadian Corps is being brought to the south to take over the rôle of Reserve Corps at the junction of the British and French Armies in replacement of the 22nd Corps, which occupied that rôle until it was ordered to the CHAMPAGNE front. In order that the enemy may be deceived as to the destination of the Canadian Corps in the event of his discovering that it has been withdrawn from the ARRAS front, Canadian wireless personnel has been sent to the Second Army area,[11] where they have taken over certain wireless zones.

"(b) To prevent the enemy from discovering the arrival of the Canadian Corps in this region, they will not take over from the 4th Australian Division until 'Y' night. This will necessitate a proportion of the troops of the Fourth Australian Division remaining in the line in this sector until 'Y' night. As the Fourth Australian Division will be required to participate in the attack it is proposed to distribute one brigade to hold the whole of the line from 'W' night onwards. This will enable the remaining two Brigades to be withdrawn, given a day or two's rest, and allow of their part in the operation being fully explained to them. The place of these two Brigades in rear of the line Brigade will be taken over by Canadian Divisions.

"(c) In order to deceive our own troops as to the cause of the coming down here of the Canadians, a rumour is going abroad that the Canadian Corps is being brought down with the object of relieving the Australian Corps in the line. To most of the Australian Corps this would appear to be an obvious reason for their coming, as the idea has been mooted on former occasions. While it is not intended that this rumour should be promulgated, it is not desired that anyone should disclose the actual facts. This idea, together with the idea put forth in paragraph 3 (a), should do much to prevent the real facts from becoming known."[12]

The references to "W," "X," "Y" and "Z" days and nights in the above memo, are to the successive days preceding Zero day--known briefly as "Z" day, on which the battle was to open. The actual _date_ of "Z" day was kept a close secret by the Army Commander and the three Corps Commanders concerned, until a few days before the actual date; while the actual moment of assault, or "Zero" hour, was not determined or made known until noon on the day preceding the battle, after a close study of the conditions of visibility before and after break of day, on the three preceding mornings.

But these arrangements were directed only towards the prevention of a premature disclosure of our intention to attack to the enemy, to our own troops, and through them to the civilian public, and to enemy agents, whose presence among us had always to be reckoned with. It still remained to carry out our battle preparations in a manner which would preclude the possibility of detection by enemy aircraft, either through direct observation, or by the help of photography.

Accordingly I issued orders that all movements of troops and of transport of all descriptions, should take place only during the hours of darkness, whether in the forward or in the rear areas; and in order to keep an effective control over the faithful execution of these difficult orders, I arranged for relays of "police" aeroplanes, furnished by our No. 3 Squadron, to fly continuously, by day, over the whole of the Corps area, in order to detect and report upon any observed unusual movement.

At the same time, the normal work on the construction of new lines of defence, covering Amiens, in my rear areas, which had been continuously in progress for many weeks and was still far from complete, was to continue, with a full display of activity; so that the enemy should be unable to infer, from a stoppage of such works, any change in our attitude.

Orders were also given to discourage the usual stream of officers who ordinarily visited our front trenches prior to an operation, and who often, thoughtlessly, made a great display of unusual activity, under the very noses of the enemy front line observers, by the flourishing of maps and field-glasses, and by bobbing up above our parapets to catch fleeting glimpses of the country to be fought over. Such reconnaissance, however desirable, was to be confined to a few senior Commanders and Staff Officers. All subordinates were to rely upon the very large number of admirable photographs, taken regularly from the air, both vertically and obliquely, by the indefatigable Corps Air Squadron. These served excellently as a substitute for visual observation from the ground.

The prohibition against the movement of any transport in the daylight naturally very seriously hampered the freedom of action of the troops of all arms and services, but was felt in quite a special degree by the whole of the Artillery. Over 600 guns of all natures had to be dragged to and emplaced in their battle positions, and there camouflaged, each gun involving the concurrent movement of a number of associated vehicles. A full supply of ammunition had to be collected from railhead, distributed by mechanical transport to great main dumps, and thence taken by horsed vehicles for distribution to the numerous actual gun-pits.

As the amount of ammunition to be held in readiness for the opening of the battle averaged 500 rounds per gun, it became necessary to handle a total of about 300,000 rounds of shells and a similar number of cartridges of all calibres, from 3½ to 12 inches, not to mention fuses and primers, or the immense bulk and weight of infantry and machine-gun ammunition, bombs, flares, rockets, and the like, for the supply of all of which the artillery was equally responsible.[13] The great amount of movement involved in the handling and dumping of all these munitions, and the deterrent difficulties of carrying out all such work only during the short hours of darkness, must be left to the imagination.

The artillery was, however, confronted, for the first time, with a difficulty of quite a different nature. In the previous years of the war every gun, _after_ being placed in its fighting pit or position, had to be carefully "registered," by firing a series of rounds at previously identified reference points, and noting the errors in line or range due to the instrumental error of the gun, which error varied with the gradual wearing-out of the gun barrel. By these means, battery commanders were enabled to compute the necessary corrections to be applied to any given gun, at any one time or place, so as to ensure that the gun would fire true to the task set.

Such registration naturally involved, for a large number of guns, a very considerable volume of Artillery fire, the extent of which would speedily disclose to the enemy the presence of a largely increased mass of Artillery, and would inevitably lead him to the conclusion that some mischief was afoot. Fortunately, however, the rapid evolution during the war of scientific methods had by this juncture placed at my disposal a means of ascertaining the instrumental error of the guns on a testing ground located many miles behind the battle zone. This method was known as "calibration," and consisted of the firing of the gun through a series of wired screens, placed successively at known distances from the muzzle of the gun. The whole elements of the flight of the projectile could then be accurately determined by recording the intervals of time between its passage through the respective screens. From these data could be deduced the muzzle velocity, the jump, the droop and the lateral error of each gun.

Simple and obvious as was the principle of such an experiment, the merit of the new process of calibration lay in the remarkable rapidity and accuracy with which the electric and photographic mechanism employed made the necessary delicate time observations, correct to small fractions of a second, and automatically deduced the mathematical results required. The calibration hut, in which this mechanism was housed, became one of the show spots to which visitors to the Corps area were taken to be overawed by the scientific methods of our gunners.

In the early days of August the calibration range of the Australian Corps was a scene of feverish activity. All day long, battery after battery of guns could be seen route-marching to the testing ground, going through the performance of firing six rounds per gun, and then route-marching back again the same night to its allotted battle position. So rapid was the procedure that long before he had reached his destination the Battery Commander had received the full error sheet of every one of his guns, and by means of it was enabled to go into action whenever required without any previous registration whatever. This great advance in the art of gunnery contributed in the most direct manner to the result that when these 600 guns opened their tornado of fire upon the enemy at daybreak on August 8th, the very presence in this area of most of them remained totally unsuspected.

The manner of the employment of the ponderous mass of Heavy Artillery at my disposal will be referred to later. The action of that portion of the Field Artillery which was to become mobile in the concluding phases of the battle has already been dealt with. It remains only to describe, in outline, the arrangements made for the normal barrage fire of the Field Artillery during the first phase.

It has been my invariable practice to reduce the barrage plan to the simplest possible elements, avoiding in every direction the over-elaboration so frequently encountered. By following these principles not only is the actual preparatory work of the Artillery greatly reduced in bulk and simplified in quality, but also the liability to mistake and to erratic shooting of individual batteries or guns, and consequent risks of damage to our own Infantry, are greatly diminished. These advantages are bought at the small price of calling upon the Infantry to undertake, before the battle, such rectifications and adjustments of our front line as would accommodate themselves to a straight and simple barrage line. This is in sharp contrast to the much more usual procedure which prevailed (and persisted in other Corps to the end of the war) of complicating the barrage enormously in an attempt to make it conform to the tortuous configuration of our Infantry front line.

For the present battle it was accordingly arranged that the barrage should open on a line which was _dead straight_ for the whole 7,000 yards of our front, and the Infantry tape lines,[14] which were to mark the alignment of the Infantry at the moment of launching the assault, were to be laid exactly 200 yards in rear of this Artillery "start line." The barrage was to advance, in exactly parallel lines, 100 yards at a time, at equal rates along the whole frontage. These rates were 100 yards every 3 minutes, for the first 24 minutes, and thereafter 100 yards every 4 minutes, until the conclusion of the time-table at 143 minutes after Zero. By such a simple plan every one of the 432 field guns engaged was given a task of uniform character.

Great as was the care necessary to conceal all Artillery preparations, it required still greater thought and consideration to keep entirely secret the presence behind the battle front of some 160 Tanks, and particularly to conceal their approach march into the battle. To both combatants, the arrival of a Tank, or anything that could be mistaken on an air photograph for a Tank, had for long been regarded as a sure indication of coming trouble. And, therefore, imputing to the enemy the same keenness to detect, in good time, the presence of Tanks, and the same nervousness which we had been accustomed to feel when prisoners' tales of the coming into the war of enormous hordes of German monsters had been crystallized by the reports of some excited observer into a definite suspicion that the fateful hour had arrived, I considered it wise to repeat on a much elaborated scale all the precautions of secrecy first employed for this purpose at Hamel.

It is quite easy to detect from an air photograph the broad, corrugated track made by a Tank, if the ground be soft and muddy enough to record such an impression. Consequently, Tanks were forbidden to move across ploughed fields or marshy land, and were confined to hard surface. They moved only in small bodies, and only at night, and were carefully stabled, during the daylight, in the midst of village ruins, or under the deep shade of woods and thickets. Thus, by daily stages, and by cautious bounds, each Tank or group of Tanks ultimately reached its appointed assembly ground, from which it was to make its last leap into the thick of the battle, where it would arrive precisely at Zero hour.

But that last leap was just the whole difficulty. For the Tank is a noisy brute, and it was just as imperative to make him inaudible as to make him invisible. By a fortunate chance, the noise and buzz made by the powerful petrol engines of a Tank are so similar to those of the engines of a large-sized bombing plane, as for example of the Handley-Page type, especially if the latter be flying at a comparatively low altitude, that from a little distance off it is quite impossible to distinguish the one sound from the other.

It was therefore possible to adopt the conjurer's trick of directing the special attention of the observer to those things which do not particularly matter, in order to distract his attention from other things which really do matter very much. In other words, a flight of high-power bombing planes was kept flying backwards and forwards over the battle front during the whole of that very hour, just before dawn, during which our 160 Tanks were loudly and fussily buzzing their way forward, along carefully reconnoitred routes, marked by special black and white tapes, across that last mile of country which brought them up level with the infantry at the precise moment when the great battle was ushered in by the belching forth of a volcano of Artillery fire.

The subterfuge succeeded to perfection, as was obvious to observers and confirmed by the subsequent narratives of prisoners. The German trench garrisons and trench observers were fully occupied in listening to the hum of the bombing planes, in watching their threatened visitation for their customary "egg" dropping performances, in engaging them with rifle fire, and in holding themselves in readiness to duck for cover should they come too near. They never suspected for a moment that this was merely a new stratagem of "noise camouflage," and that the real danger was stalking steadily and relentlessly towards them over the whole front, upon the surface of the ground, instead of in the air.

But the trick would not have succeeded so well, or would perhaps have failed altogether, if the employment of those planes had been confined to the morning of the battle. Such an unusual demonstration might have aroused vague suspicions sufficient to justify a "stand to arms" and a preparedness for some further activity on our part. And what we had most to fear was the danger of "giving the show away" in the last ten minutes. For it would have taken much less than that time for nervous German trench sentries, by the firing of signal rockets, to bring down upon our front line trenches, crowded as they were with expectant fighters, a murderous fire from the German Artillery.

Consequently the puzzled enemy was treated to the spectacle of an early morning promenade by these same bombing planes on every morning, for an hour before dawn, during several mornings preceding the actual battle day. Doubtless the first morning's exhibition of such apparently aimless air activity in the darkness really startled him. After two or three repetitions, it merely earned his contempt. By the time the actual date arrived he treated it as negligible. All prisoners interrogated subsequently agreed that neither the presence nor the noisy approach of so mighty a phalanx of Tanks had been in the least suspected up to the very moment when they plunged into view out of the darkness, just as day was breaking.

The force of Tanks placed at my disposal for the purposes of this battle comprised the 2nd, 8th and 13th Tank Battalions, commanded respectively by Lieut.-Colonels Bryce, Bingham and Lyon, all under the 5th Tank Brigade, commanded by Brigadier-General Courage. All these Tanks were of the Mark V. type, as used at Hamel; but there were also attached to the same Brigade a Battalion of Mark V. (Star) Tanks, of still later design, under Lieut.-Colonel Ramsay-Fairfax, and also a full Company of 24 Carrying Tanks, under Major Partington. These Carrying Tanks were not employed in fighting, but were of wonderful utility in the rapid transport of stores of all descriptions across the battle zone; and in carrying the wounded out of the battle on their return journey. I am confident that each of these Tanks was capable of doing the work of at least 200 men, with an almost complete immunity from casualty.

There were thus available to me 168 Tanks in all, and their dispositions have been already indicated in sufficient detail in