Polish forces temporarily halted the German Third Army's advance from East Prussia on the first day of the Invasion of Poland.
Key Facts
- Date
- 1 September 1939
- Location
- Near Janowo and Krzynowłoga Mała, Poland
- German formation
- German Third Army (incl. Panzer Division Kempf, 1st Corps, Wodrig Corps)
- Polish formation
- 20th Infantry Division; elements of 11th Cavalry Regiment
- Key obstacle
- Mława fortifications and swampy ground halted German advance
- Cavalry engagement
- Polish Uhlans (dismounted) stopped German 1st Cavalry Brigade along Ulatkowka river
By the Numbers
Location
Cause → Event → Consequence
The German Third Army launched an offensive from East Prussia toward Warsaw on 1 September 1939 as part of the broader Invasion of Poland. Its advance required breaking through Polish border defenses, including the fortified Mława line held by the Polish 20th Infantry Division.
German forces, including Panzer Division Kempf and two divisions of the 1st Corps, were stopped at the Mława fortifications. The Wodrig Corps could not outflank the position due to marshy terrain. Along the Ulatkowka river, dismounted Polish Uhlan cavalry repelled attacks by the German 1st Cavalry Brigade.
The Polish defenders successfully stalled the German Third Army's advance on the first day of the invasion, denying a rapid breakthrough from East Prussia toward Warsaw and demonstrating that even outnumbered Polish units could resist German pressure under favorable defensive conditions.
Belligerents & Mobilization Analysis
Side A
1 belligerent
Side B
1 belligerent