Leaving a small cavalry div. to slow down the Russian 1st Army under Rennenkampf, the rest of the German 8th moved against Samsonov's 2nd.
After intercepting Russian radio messages, Hindenberg knew where each unit was and resolved to encircle them. The German XVII Corps and I Reserve Corps hit the Russian right while von Francois' I Corps hit the left. The XX counter-attacked the centre. Successfully turning both flanks, the Germans caused the Russian to fall back in dissarray, further confused by poor communication and lack of appreciation of the situation. The trap was closed when von Below's 1st Reserve and von Francois' 1st Corps extended to complete the encirclement and the Russian 2nd was effectively destroyed. Samsonov, after ordering the retreat on the 29th dissappeared, thought to have committed suicide. Rennenkampf's 1st Army made no move to assist.

German 8th Army

Number engaged :

n/a

Casualties :

13,000

Russian 2nd Army

Number engaged :

n/a

Casualties :

125,000