The Russian front now followed the west bank of the Bzura for a few miles, changed to the eastern bank following the river until it met with the Rawka, from there a line of trenches passed south and east of Balinov and from there to Skiernievice. Von Mackensen concentrated a considerable army at Balinov and had on the 1st of February about a hundred and forty thousand men there. That night, with the usual artillery preparation, he moved from Balinov against the Russian position at the Borzymov Crest. The Germans lost heavily but drove forward into the enemy's line, and by the 3d of February had almost made a breach in it. This point, however, could be readily reinforced and troops were hurried there from Warsaw in such force that on February 4th the German advance was checked. Von Mackensen had lost heavily, and by the time it was checked he had become so weak that his forces yielded quickly to the counter-attack and were flung back. This was the last frontal attack upon Warsaw. Von Hindenburg then determined to attack Warsaw by indirection. Austria was instructed to move forward along the whole Carpathian front, while he himself, with strong forces, undertook to move from East Prussia behind the Polish capital, and cut the communications between Warsaw and Petrograd. If Austria could succeed, Przemysl might be relieved, Lemberg recaptured, and Russia forced back so far on the south that Warsaw would have to be abandoned. On the other hand if the East Prussia effort were successful, the Polish capital would certainly fall. These plans, if they had developed successfully, would have crippled the power of Russia for at least six months. Meantime, troops could be sent to the west front, and perhaps enable Germany to overwhelm France. By this time almost all of Poland west of the Vistula was in the power of the Germans, while three-fourths of Galicia was controlled by Russia. Von Hindenburg now returned to his old battle-ground near the Masurian Lakes. The Russian forces, which, at the end of January, had made a forward movement in East Prussia, had been quite successful. Their right was close upon Tilsit, and their left rested upon the town of Johannisburg. Further south was the Russian army of the Narev. Von Hindenburg determined to surprise the invaders, and he gathered an army of about three hundred thousand men to face the Russian forces which did not number more than a hundred and twenty thousand, and which were under the command of General Baron Sievers. The Russian army soon found itself in a desperate position. A series of bitter fights ensued, at some of which the Kaiser himself was present. The Russians were driven steadily back for a week, but the German stories of their tremendous losses are obviously unfounded. They retreated steadily until February 20th, fighting courageously, and by that date the Germans began to find themselves exhausted.