To achieve this result against superior numbers, manoeuvre
was the only way, and by the term " manoeuvre " Ludendorff
understood the preparation and sudden delivery of a destructive
blow by locally superior force upon that part of the enemy's
system which was the key of the whole. In the present case,
this key position, Ludendorff held, was the Russian X. Army in
the foreground of the Masurian lakes. In this quarter, and also
between Mlava and Myszyniec, Russian offensives were matur-
ing as early as mid-Jan., and in any case Hindenburg's head-
quarters had to consider the question of a preventive offensive
in E. or W. Prussia or both. But the operative aim became
higher as soon as it was known that Conrad meant to attempt
the relief of Przemysl by winning through to the San and the
Dniester. The four new army corps completing their training
in Germany were asked for, for the purpose of a winter offensive
which should not only anticipate that of the enemy, but also,
in conjunction with Conrad's effort, " decide the whole war."
These four corps (XXXVIII.-XLI. Res.) were Falkenhayn's
cherished reserve, with which he meant to parry any great
crisis that might arise out of the " Winter Battle of Champagne "
then, in progress, and himself to attempt a decisive offensive in
France. 1 From the contemplated blow in Prussia he expected
no more than the temporary and local disablement of the enemy,
so that he did not think it necessary to coordinate the effort
closely in date or direction with Conrad's advance. Neverthe-
less, " with a heavy heart," as he says, he surrendered the four
corps to the east, though at first till the Champagne crisis cleared
in March he reserved the right to withdraw them again.
Actually, the XXI. Active Corps of Alsace-Lorrainers was sent
from the French front, the XLI. Res. Corps taking its place
there; the other three, with the XXI., went to E. Prussia at the
end of Jan. and constituted the new X. Army (General-Oberst
von Eichhorn).
The two operations with which the campaign of 1915 began in the W. were not, in the strict sense, coordinated, though their combined effect, owing to geographical conditions, was expected to be the destruction, according to Ludendorff, or the prolonged paralysis according to Falkenhayn, of Russia's offen- sive power.
The Carpathian Winter Battles. Owing to the relatively low development of Hungarian lateral railways the Galician laterals were in the hands of the Russians it was not feasible for Conrad to form a really important offensive mass in the eastern Carpathians and the Bukovina, as Hindenburg did in the region of the Masurian lakes, without great loss of time. The struggle therefore resolved itself into surgings of frontally-opposed tides, the one seeking to break into the Hungarian plain, the other to rescue Przemysl. Although, the lines being for the most part discontinuous, tactical and local outflanking efforts, for the time and place decisive, were constantly made by both sides, there was no systematic attempt at strategic envelopment on either. At one moment indeed (Feb. 20), Pflanzer-Baltin's army group, victorious in Bukovina, sought to wheel in on the rear of the battle-field of the German South Army; and at a later stage the Russian Dniester forces were heavily reenforced for the purpose of driving Pflanzer-Baltin away and so gaining the flank of Linsingen. But in the main the opposed tides affronted each other and were broken, each in turn. In W. Galicia, the Russian offensive of Jaslo came to a standstill in the first days of January, and for the next three months nothing of importance took place W. of Gorlice. Here the Russian III. Army (Radko Dimitriev) and the Austro-Hungarian IV. Army (Archduke Josef Ferdinand) were opposed. In the middle Carpathians, where Brussilov's VIII. Army was opposed by Boroevic's III. Army and by the left wing of the widespread Pflanzer-Baltin group, the year opened with the evacuation by the defenders of the important Uszok Pass, under a local threat of envelopment. The Dukla Pass and the adjacent mountain region had already been lost, and from the Uszok the withdrawal spread east to the
1 The German contingent of the South Army had been formed from local reserves already in the east. Its staff was formed from that of the II. Corps.
Volocz and Wyszkov Passes. In the eastern Carpathians and Bukovina the Russian Dniester group (Webel) pushed back the light forces which Pflanzer-Baltin had in the foreground of the mountains, but in the last week of Jan. the arrival of the Austrian XIII. Corps from Serbia gave Pflanzer-Baltin enough forces to enable him on the 3ist to begin the reconquest of the lost ground. Meanwhile, the right of Boroevic's III. Army had held on, in spite of the loss of the Uszok and the Dukla Passes, and it was now reenforced. After covering the assembly of the German South Army about Munkacs, this wing was to consti- tute the striking force of Conrad's offensive for the relief of Przemysl, the South Army (including Hofmann's Austrian Corps facing the Volocz Pass) following it in echelon on the right.
The offensive began on Jan. 23, and as usual in this part of the eastern theatre, met at first only light forces of the Russians. The whole Austrian line, from E. of the Dukla to the Wyszkow Pass, moved forward, the left wing of Pflanzer-Baltin conform- ing. The Uszok, Volocz and Wyszkow passes were retaken by the South Army, and Boroevic's striking force reached and passed the upper San (line Czeremcza-Baligrod-Lutowiska- Borynia-Smorze) by Jan. 31. But the Russians had already answered by accelerating their projected offensive against the centre and left of Boroevic (front Mezolaborcz-Konieczna) and especially southward and south-westward from the Dukla. From this point the battle was a contest of will-power and man- power. The inactive fronts were stripped of more and more divisions. Early in Feb. Bohm Ermolli's headquarters returned from Poland to their old place on the right of the III. Army (front Lupkow Pass-Uszok Pass), and on the other side Letchit- sky's IX. Army headquarters were withdrawn from the Nida for the Dniester theatre. Between the end of January and the end of April the strength of the opposed forces in Poland west of the Vistula were approximately halved. In the event the Grand Duke Nicholas not only succeeded, during the first three weeks of Feb., in checking (and in forcing back somewhat) the Austrians on the Upper San, but considerably enlarged his gains S. and S.W. of the Dukla Pass, taking Mezolaborcz and the Lupkow Pass, and penetrating the Laborcz and Ondava valleys. On the other hand the German South Army made its way for- ward, very slowly, astride the Munkacs-Stryi railway.
Further E., the counter-offensive campaign of Pflanzer-Baltin, begun on Jan. 31, was successful in clearing all Bukovina and the Carpathian foreground as far as the Pruth on the right and the Dniester in the centre, but its left, attempting to inter- vene in the rear of Linsingcn's opponents, was involved in heavy fighting about Krasna on the Lomnica, and in the last week of Feb. the heavy counter-attacks of the assembling Russian IX. Army drove the centre from its forward position on the Dniester. By mid-March, Pflanzer-Baltin had been forced back still farther to a line marked by the upper Lomnica-Solotvina (on the Bistrica)-Czernelica-Horodenka-Snyatin-Czernowitz, on which operations came to a standstill. These operations were however of secondary importance in which only some 10% of the whole forces of each side were concerned.
The real crisis, which culminated in March, was on the front between the upper San and the head of the Ondava valley, N.E. of Bartfcld (Bartfa). As in Feb., the right of the Austrians sought to force a way to Przemysl now in extremity and the right of the Russians to enlarge the bridge-head in front of the Dukla and Lupkow Passes. The fighting was again intense, for the Austro-Hungarian II. Army had been reenforced for a last effort; but in the main its advance on Przemysl was definitely stayed by the middle of the month, while the Russians in the Dukla region made continuous, if slow, progress. The German South Army progressed along the railway to Tuchla, but at this stage of the battle its advance had not and could not have any great result, and its left was held up for weeks before the strong positions known as Zwinin and Ostry, covering Koziowa. Finally, on March 20, sure of the imminent surrender of Prze- mysl (which in fact fell on the 23rd) the Russians launched all along the front of the Austrian III. Army new attacks which, fed by troops released from the blockade of Przemysl, drove that
