The Opening Moves of Germany’s Blitzkrieg

When Germany launched its invasion of Poland on September 1, 1939, it marked the beginning of World War II in Europe. The German war machine executed a carefully planned blitzkrieg strategy, with three army groups advancing along multiple fronts. The 14th Army Group, after reorganization, moved south to capture Krakow, while the mechanized 22nd Corps crossed the Dunajec River to cut off Polish forces retreating eastward across the Vistula.

By September 9, Army High Command ordered the 22nd Corps to break through Polish defenses along the San River, advancing north toward Chelm to link up with General Guderian’s 19th Corps moving south from East Prussia. This pincer movement aimed to encircle Polish forces east of Warsaw, demonstrating Germany’s new approach to mobile warfare that would characterize the early years of World War II.

The Polish Army’s Precarious Position

As German forces swept through western Poland, only General Kutrzeba’s Poznan Army remained unengaged. The German High Command initially planned to bypass this Polish force to strike deep into Poland’s heartland. When Polish commanders realized German intentions, Kutrzeba requested permission to attack the advancing German 8th Army from the south. Marshal Smigly-Rydz refused, preferring to concentrate forces along the Vistula River.

During their eastward retreat toward Warsaw, the Poznan Army faced relentless Luftwaffe attacks but avoided major ground engagements. They eventually joined remnants of the Pomorze Army at Kutno, a vital transportation hub. By September 8, Kutrzeba again proposed attacking the German 8th Army with his combined forces of 10 infantry divisions and 2.5 cavalry divisions – still a formidable fighting force despite earlier setbacks.

The Battle of Bzura: Poland’s Last Major Offensive

On September 9, Polish forces launched their counterattack near the Bzura River, marking the campaign’s only major Polish offensive. The initial assault caught the German 8th Army by surprise, forcing retreats and inflicting heavy casualties. A Polish officer later recounted searching dead German soldiers for maps – finding one that became their “most valuable trophy of the entire war.”

Despite early successes, Polish forces soon faced critical shortages of food, ammunition, and supplies. German commanders Rundstedt and Manstein saw the Polish offensive not as a threat but as an opportunity to encircle and destroy a significant portion of Poland’s remaining forces. They began coordinating a massive counter-encirclement, pulling units from the 10th and 14th Armies to reinforce the 8th Army.

The Closing of the Kutno Pocket

By September 12, Kutrzeba realized his forces risked complete encirclement near Kutno. Polish attempts to break out southeast met with initial success but ultimately failed as German forces tightened their ring. The Luftwaffe shifted focus from Warsaw to the Kutno pocket, dropping 328 tons of bombs that inflicted horrific casualties.

The Polish defense collapsed on September 18, with 40,000 soldiers captured that day alone. Only small groups escaped, many using the Kampinos Forest for cover. SS officer Kurt Meyer, later a general, acknowledged Polish bravery despite Nazi ideology: “We deny the Polish army’s courage unjustly…every battle at Bzura was fought with great ferocity and bravery.”

The Soviet Invasion from the East

On September 17, as German forces took Brest-Litovsk, Soviet troops invaded eastern Poland under secret protocols of the Molotov-Ribbentrop Pact. The Red Army’s two fronts – Belarusian and Ukrainian – comprised over 20 infantry divisions, 15 cavalry divisions, and 9 tank brigades. Initially mistaken for allies, Soviet forces quickly disarmed Polish units they encountered.

This two-front invasion proved catastrophic for Poland. President Ignacy Moscicki and government officials fled to Romania on September 17, only to be interned under German pressure. Approximately 60,000 Polish troops reached Hungary, 30,000 escaped to Romania, and 15,000 to Lithuania, with many later forming new Polish units in France.

The Siege and Fall of Warsaw

With eastern Poland occupied by the Soviets, German forces concentrated on reducing remaining Polish resistance. By September 15, Warsaw was encircled. Hitler, wary of costly urban combat, demanded surrender before authorizing full-scale assault. When Poland refused, the Luftwaffe targeted water and power systems while artillery pounded defenses.

After days of bombardment, with civilians facing starvation and disease, General Juliusz Rommel surrendered Warsaw on September 27. The Modlin garrison held out until September 28, while coastal defenses at Gdynia and the Hel Peninsula resisted until early October. Poland’s organized military resistance had ended after 36 days.

The Aftermath and Fourth Partition

Casualty figures reveal the campaign’s brutality: approximately 66,300 Polish dead, 130,000 wounded, and between 400,000-700,000 captured. Germany suffered lighter losses but still lost 217 tanks and 285 aircraft. On September 28, Ribbentrop signed the German-Soviet Boundary Treaty in Moscow, formalizing Poland’s fourth partition (following those of the 18th century).

The treaty’s secret protocols authorized both powers to suppress Polish resistance in their zones. What followed was six years of unparalleled suffering – mass executions, deportations, and systematic destruction of Poland’s leadership class. While German troops celebrated victory, Poland entered what one historian called “the beginning of hell on earth.”

The Battle of Bzura demonstrated Polish courage against overwhelming odds while highlighting Germany’s military innovations. Its legacy endures as both a tactical milestone in blitzkrieg warfare and a tragic prelude to Poland’s wartime martyrdom. The campaign’s lessons about coalition warfare, civilian resilience under siege, and the costs of unpreparedness remain relevant for military historians and strategists today.