The new commander, Hindenburg, had not yet been employed in the War. His chief of staff, Ludendorff, reached supreme head quarters at Coblenz on the 22nd and the situation in the East was explained to him. He immediately ordered the troops retreating in front of Rennenkampf to halt at once and to prevent him from pursuing, and issued instructions for a concentration against Sam sonov. General Hindenburg joined Ludendorff's train at Hanover and took over the command at Marienburg on the 23rd.
Luckily for the new command, Hoffmann, the chief of the operations section under Prittwitz, had already carried out many steps facilitating the concentration desired by Ludendorff, and the situation, though alarming, had not grown worse since the supersession of Prittwitz. Samsonov's right was indeed well over the frontier near Ortelsburg and his left between Neidenburg and Dzialclowo (Soldau) but the Russian advance appeared to be slowing up. The German XX. Corps had taken up a position north of Neidenburg and was awaiting attack. The leading units of the I. Corps were detraining south of Deutsch Eylau and were moving up on the right of the XX. Corps. The 3rd Res. division had detrained at Allenstein and was moving up on the left of the XX. Corps. A Landwehr division and units from the Vistula garrison troops were also coming up. Thus, a strength of about six or seven divisions had been collected to oppose ten divisions and three cavalry divisions of Samsonov's army.
No decisive results could be expected from such strength, and decisive operations were the Germans' only hope. The most im portant feature of the situation, however, was that Rennen kampf had made no forward move since Gumbinnen and had lost all touch with the enemy in front of him. Ludendorff there fore conceived the idea of withdrawing all the troops from Ren nenkampf's front, with the exception of the cavalry division, and of directing them against the right flank of Samsonov's army. An other four divisions thus obtained would give him an actual su periority over Samsonov and the direction of their attack might indeed be decisive.
XIII. Corps) had reached the frontier, with the 4th Cay. Div. well behind on the right. The left wing (XV. and I. Corps) .was just short of the frontier, with the 6th and 15th Cay. Divs. cover ing it. Of the XXIII. Corps, one division was two days' march behind the left wing and the other had not yet detrained at War saw. The troops had been marching for a week across the desert area north of Ostroleka, over execrable roads in very hot weather. Much of the transport had been left behind, the men were tired and unfed and numbers had been much reduced by sickness. No contact had been gained with the enemy and the army was already more than 24 hours late in crossing the frontier. Reports from Rennenkampf of his victory at Gumbinnen and, during his ad vance westwards on the 24th and 25th, of the signs of a hurried retreat on the part of the Germans, brought further urgings from Jilinsky to Samsonov to hurry. Samsonov obeyed to the best of his ability, and by the morning of the 26th his position was as follows : His centre of two corps (XIII. and XV.) was advancing north west and was close on the line Allenstein-Hohenstein. On his right was one corps (VI.) and the 4th Cay. Div. at Rothfliess, at two days' march from the centre. On his left was a corps (I.) and the 6th and 15th Cay. Divs. near Koschlau, at one day's march from his centre. The XXIII. Corps troops which were up were moving into the gap between the centre and the left. His forces were thus much dispersed.
Reconnaissance had been bad and he had little information as to the enemy's dispositions. He seems to have thought that the Germans flying in front of Rennenkampf had already crossed his front in their march to the Vistula and that he was too late to cut them off. He had deviated from his instructions to advance with his left on Allenstein and now had practically the whole of his force to the west of that town. He had no knowledge of the whereabouts of Rennenkampf's army and did not realize that he was increasing the space between the two Russian armies and thereby facilitating the German operations. His supply system had broken down utterly and his men were half-famished and worn out with the fatigue of excessive marching. The signal serv ice had also broken down and orders had been sent out to corps by wireless. The Russian signals were easily read by the Ger mans, who thus had absolutely accurate information as to their opponents' dispositions and intentions.