The battle begins!
It is the 1st of August 1914, Germany has just declared war on Russia, because Russia has refused to cancel its mobilization. Von Moltke immediately puts deployment plan “Aufmarsch II Ost” into effect. As a result, France also starts mobilizing.
Joffre insists on attacking Germany as soon as possible, simultaneously with Russia, because that offers the only chance for a quick victory. However, the French government first wants to be assured of British support. After much deliberation, the British government is finally prepared to give the French a 'blank cheque'. Britain will honor the naval agreement and protect the French Channel coast by declaring the Channel and Southern North Sea a 'neutral zone', i.e. a demilitarized zone under the protection of the 'neutral' Royal Navy. The BEF is emphatically not sent to France and the British also demand that Belgian neutrality must be respected. The French government is satisfied with this and declares war on Germany on 12 August. That same day, the first French troops enter southern Alsace, whereupon Germany invades Luxembourg to prevent the French from doing so. Two days later, Joffre launches a major offensive in Lorraine.
In the meantime, the fighting in the east has been limited to a few skirmishes between German and Russian reconnaissance troops. Germany has also taken some border towns, such as Kalisz and Mlawa. In East Prussia, the 1st and 2nd Armies are preparing an offensive against the Narew line, when suddenly the Russian 1st Army led by
Rennenkampf invades East Prussia on 15 August. With this, Russia fulfills the
military agreement with France. The German 1st Corps commanded by
von François counter-attacks at Stallupönen, but has to withdraw. When Rennenkampf orders a rest on 20 August, the 4th Army led by the
Crown Prince seizes the opportunity to attack the Russian 1st Army, resulting in the Battle of Gumbinnen. Because the 1st Corps attacks too early, this attempt to defeat the Russians fails and the 4th Army retreats behind the Angerapp. On 23 August, Rennenkampf attacks this line at Darkehmen. Now the Saxon (3rd) Army commanded by
von Hausen comes to the aid of the Crown Prince by attacking the Russian flank from the south and cutting off the supply lines. In the ensuing Battle of Darkehmen, the Russian 1st Army is almost completely destroyed. With only a few divisions, Rennenkampf manages to escape to Kovno.
Encouraged by Rennenkampf's initial success,
Samsonov invades East Prussia from the south with his 2nd Army on 21 August. Based on intercepted unencrypted radio messages, von Moltke knows when and where the Russians will attack and has ordered the 1st and 2nd Armies to withdraw into the woods to prepare a trap. Unaware of the strength of the German presence, Samsonov's army marches straight into the arms of the 1st army led by
von Kluck. In the battle that follows, later named after the nearby hamlet of 'Tannenberg', the Russian 2nd army is also almost completely destroyed, after which Samsonov commits suicide on 31 August. The remnants of his army retreat behind the Narew line.
After these victories, there is great joy among the German army command, but they are also amazed. The Russian attacks seem poorly organized, were the Russians not aware of the strength of the German armies in East Prussia? The lack of supplies, the unmotivated and hungry soldiers, the unencrypted radio messages, the lack of coordination… Is this the feared Russian army? And why did only two armies attack?
Von Prittwitz's 2nd army hardly needed any action! Where are the other Russian armies? However, the answer to that last question will come soon…
Two strong Russian armies are advancing in eastern Galicia. The 3rd k.u.k. army cannot compete against this superior force and has to retreat towards the
fortress of Przemysl. This creates a dangerous situation for the 1st and 4th k.u.k. armies, which have already invaded Russian Poland. Von Moltke is shocked by this news and panics; when the k.u.k. armies collapse, nothing stands in the way for the Russians to invade Silesia and pushing on towards Berlin! To prevent this disaster, he decides to immediately send the 3rd army to Silesia, reinforced with two additional army corps from the 2nd army. After all, the danger has passed in East Prussia for the time being. Von Moltke also orders the 1st and 2nd armies to go on the offensive as quickly as possible, in order to bind as many Russian troops as possible, so that they cannot be deployed in Galicia.
On 4 September, von Kluck's 1st Army begins the Narew offensive, also known as 'the battle of the Narew'. Von Kluck concentrates on the obsolete fortresses of Pultusk and Ostroleka in order to bypass the more modern fortresses of Rozan and Lomza. Meanwhile, the 2nd Army makes several attempts to take
Osowiec Fortress, but the surrounding marshes make this fortress impregnable. The Russian 9th Army led by Lechitsky, consisting largely of poorly trained reserve divisions, tries to hold out behind the Narew as long as possible. However, it cannot compete with the superior numbers and firepower of the Germans and retreats behind the Bug. The remnants of the Russian 2nd Army also retreat, until they set up a new defense at Zambrow. The German 1st Army is now losing strength, as it has marched more than 100 km away from the railheads of Mlawa and Ortelsburg in just in 10 days. New supplies must be brought in by horses over dirt roads and improvised bridges. This ends the offensive on 14 September.
In Galicia, the 1st, 3rd and 4th k.u.k. armies have retreated behind the San with heavy losses, but are able to hold that line. The 2nd k.u.k. army was rushed north from Serbia, but arrived too late, it can do no more than defend the mountain passes in the Carpathians. The war has now lasted almost 7 weeks and the 'Battle of Poland' is still undecided. The break is being used by the belligerents to prepare for round two... Meanwhile, in the west, the French invasion fails hopelessly. After suffering heavy losses in the
Battle of Lorraine, the French retreat across the border. This turns the western front into a stalemate.
