The 2nd Panzer Division (English: 2nd Tank Division) was an armoured division in the

German Army The German Army (, 'army') is the land component of the armed forces of Federal Republic of Germany, Germany. The present-day German Army was founded in 1955 as part of the newly formed West German together with the German Navy, ''Marine'' (G ...

, the Heer, during

World War II World War II or the Second World War (1 September 1939 – 2 September 1945) was a World war, global conflict between two coalitions: the Allies of World War II, Allies and the Axis powers. World War II by country, Nearly all of the wo ...

. Created as one of the original three German tank divisions in 1935, it was stationed in

Austria Austria, formally the Republic of Austria, is a landlocked country in Central Europe, lying in the Eastern Alps. It is a federation of nine Federal states of Austria, states, of which the capital Vienna is the List of largest cities in Aust ...

after the

Anschluss The (, or , ), also known as the (, ), was the annexation of the Federal State of Austria into Nazi Germany on 12 March 1938. The idea of an (a united Austria and Germany that would form a "German Question, Greater Germany") arose after t ...

and then participated in the campaigns in

Poland Poland, officially the Republic of Poland, is a country in Central Europe. It extends from the Baltic Sea in the north to the Sudetes and Carpathian Mountains in the south, bordered by Lithuania and Russia to the northeast, Belarus and Ukrai ...

(1939) and

France France, officially the French Republic, is a country located primarily in Western Europe. Overseas France, Its overseas regions and territories include French Guiana in South America, Saint Pierre and Miquelon in the Atlantic Ocean#North Atlan ...

(1940) before it returned to Poland for occupation duties (1940–1941). It took part in the Balkans campaign (1941) and then transferred to the Eastern Front in September 1941. The division fought with

Army Group Centre Army Group Centre () was the name of two distinct strategic German Army Groups that fought on the Eastern Front in World War II. The first Army Group Centre was created during the planning of Operation Barbarossa, Germany's invasion of the So ...

in the battles of

Moscow Moscow is the Capital city, capital and List of cities and towns in Russia by population, largest city of Russia, standing on the Moskva (river), Moskva River in Central Russia. It has a population estimated at over 13 million residents with ...

(1941) and

Kursk Kursk (, ) is a types of inhabited localities in Russia, city and the administrative center of Kursk Oblast, Russia, located at the confluence of the Kur (Kursk Oblast), Kur, Tuskar, and Seym (river), Seym rivers. It has a population of Kursk ...

(1943). After heavy losses on the Eastern Front it was sent to France for rehabilitation (1944). It fought in

Normandy Normandy (; or ) is a geographical and cultural region in northwestern Europe, roughly coextensive with the historical Duchy of Normandy. Normandy comprises Normandy (administrative region), mainland Normandy (a part of France) and insular N ...

and was almost completely destroyed in the

Falaise Pocket The Falaise pocket or battle of the Falaise pocket (; 12–21 August 1944) was the decisive engagement of the Battle of Normandy in the Second World War. Allied forces formed a pocket around Falaise, Calvados, in which German Army Group B, c ...

(1944). It was rebuilt once more and fought in the

Battle of the Bulge The Battle of the Bulge, also known as the Ardennes Offensive or Unternehmen Die Wacht am Rhein, Wacht am Rhein, was the last major German Offensive (military), offensive Military campaign, campaign on the Western Front (World War II), Western ...

(1944) and in the defence of the

Rhine The Rhine ( ) is one of the List of rivers of Europe, major rivers in Europe. The river begins in the Swiss canton of Graubünden in the southeastern Swiss Alps. It forms part of the Swiss-Liechtenstein border, then part of the Austria–Swit ...

(1945), surrendering to US forces at war's end.

History

Formation

The 2nd Panzer Division was formed on 15 October 1935 and was headquartered in

Würzburg Würzburg (; Main-Franconian: ) is, after Nuremberg and Fürth, the Franconia#Towns and cities, third-largest city in Franconia located in the north of Bavaria. Würzburg is the administrative seat of the Regierungsbezirk Lower Franconia. It sp ...

Bavaria Bavaria, officially the Free State of Bavaria, is a States of Germany, state in the southeast of Germany. With an area of , it is the list of German states by area, largest German state by land area, comprising approximately 1/5 of the total l ...

. It was one of three tank divisions created at the time, the other two having been the

1st First most commonly refers to: * First, the ordinal form of the number 1 First or 1st may also refer to: Acronyms * Faint Images of the Radio Sky at Twenty-Centimeters, an astronomical survey carried out by the Very Large Array * Far Infrared a ...

and 3rd Panzer Division. Germany had renounced the

Treaty of Versailles The Treaty of Versailles was a peace treaty signed on 28 June 1919. As the most important treaty of World War I, it ended the state of war between Germany and most of the Allies of World War I, Allied Powers. It was signed in the Palace ...

earlier in the year which had forbidden the country, among other things, from having tank forces, a treaty Germany had violated almost from the start by secretly developing tanks and operating a covert tank school in the Soviet Union. Under the command of

Heinz Guderian Heinz Wilhelm Guderian (; 17 June 1888 – 14 May 1954) was a German general during World War II who later became a successful memoirist. A pioneer and advocate of the "blitzkrieg" approach, he played a central role in the development of ...

the division participated in the

of Austria in 1938, covering in 48 hours but in the process losing 30 percent of its tanks to accidents and mechanical failures. It formed part of the garrison in Vienna, Austria's capital with most of its personnel now recruited from former Austria.Mitcham, p. 46.

Invasion of Poland

In early September 1939, the 2nd Panzer Division took part in the

invasion of Poland The invasion of Poland, also known as the September Campaign, Polish Campaign, and Polish Defensive War of 1939 (1 September – 6 October 1939), was a joint attack on the Second Polish Republic, Republic of Poland by Nazi Germany, the Slovak R ...

, crossing the Polish-Slowak border and advancing towards

Kraków , officially the Royal Capital City of Kraków, is the List of cities and towns in Poland, second-largest and one of the oldest cities in Poland. Situated on the Vistula River in Lesser Poland Voivodeship, the city has a population of 804,237 ...

. The division suffered heavy losses while fighting in central Poland.Stoves, p. 19.

Battle of France

In May 1940, the unit took part in the

Battle of France The Battle of France (; 10 May – 25 June 1940), also known as the Western Campaign (), the French Campaign (, ) and the Fall of France, during the Second World War was the Nazi Germany, German invasion of the Low Countries (Belgium, Luxembour ...

as a part of the

XIX Army Corps The XIX Army Corps (German language, German: ''XIX. Armeekorps'') was an Panzer corps, armored corps of the Nazi Germany, German Wehrmacht between 1 July 1939 and 16 November 1940, when the unit was renamed Panzer Group 2 (German: ''Panzergrupp ...

under the command of Guderian. The division was involved in fighting in

Belgium Belgium, officially the Kingdom of Belgium, is a country in Northwestern Europe. Situated in a coastal lowland region known as the Low Countries, it is bordered by the Netherlands to the north, Germany to the east, Luxembourg to the southeas ...

and the Mosel River valley. It arrived in the town of

Abbeville Abbeville (; ; ) is a commune in the Somme department and in Hauts-de-France region in northern France. It is the of one of the arrondissements of Somme. Located on the river Somme, it was the capital of Ponthieu. Geography Location A ...

on the 20th. The division advanced on

Boulogne Boulogne-sur-Mer (; ; ; or ''Bononia''), often called just Boulogne (, ), is a coastal city in Hauts-de-France, Northern France. It is a Subprefectures in France, sub-prefecture of the Departments of France, department of Pas-de-Calais. Boul ...

and was involved in a battle with the under-equipped French 48th Regiment on 22 May. Having overcome the defenders, the 2nd Panzers made a direct attack on the port itself which was in complete chaos. Later, the division formed the armoured element which flanked the British Expeditionary Force and forced their evacuation from Dunkirk. The 2nd Panzer Division then advanced along the River Aisne into the interior of

. At the end of the campaign in the last months of 1940, the division lost its 4th Panzer Regiment which was used as the basis for the soon-to-be-formed 13th Panzer Division.Mitcham, p. 47.

Invasion of Greece

The division was reassigned to the

XVIII Mountain Corps XVIII. ''Armeekorps'' was formed in Salzburg, Austria, on 1 April 1938, following the Anschluss of Austria into the German Reich. During the life of the XVIII. Armeekorps, they took part in the Polish campaign, Fall Weiss, and the campaign in ...

of the 12th Army on 6 April 1941 to play a role in

Operation Marita The German invasion of Greece or Operation Marita (), were the attacks on Greece by Italy and Germany during World War II. The Italian invasion in October 1940, which is usually known as the Greco-Italian War, was followed by the German invasio ...

, the invasion of Greece. The German army pushed through the south of

Yugoslavia , common_name = Yugoslavia , life_span = 1918–19921941–1945: World War II in Yugoslavia#Axis invasion and dismemberment of Yugoslavia, Axis occupation , p1 = Kingdom of SerbiaSerbia , flag_p ...

, reaching the Greek border, where they made contact with the 19th Greek Mechanized Division in the area of

Lake Dojran Doiran Lake (, ''Dojransko Ezero''; , ''Límni Dhoïráni''), also spelled Dojran Lake is a lake with an area of shared between North Macedonia () and Greece (). To the west is the city of Nov Dojran (Нов Дојран), to the east the vil ...

. On 9 April the division took the city of

Salonika Thessaloniki (; ), also known as Thessalonica (), Saloniki, Salonika, or Salonica (), is the second-largest city in Greece (with slightly over one million inhabitants in its Thessaloniki metropolitan area, metropolitan area) and the capital cit ...

and forced the surrender of the Greek Eastern Macedonia Army Section. The division, together with the 5th Mountain Division, the 6th Mountain Division and the 72nd Infantry Division, formed an attack group with the mission of advancing into the south of Greece. After the 6th Division had taken Verroia and formed a river crossing beachhead on the other side of the River Haliacmon, the 2nd Panzer Division crossed, taking

Katerini Katerini (, ''Kateríni'', ) is a city and municipality in northern Greece, the capital city of Regional Unit of Piera in Central Macedonia, Greece. It lies on the Pierian plain, between Mount Olympus and the Thermaikos Gulf, at an altitude ...

on 14 April. After the

Battle of Thermopylae The Battle of Thermopylae ( ) was fought in 480 BC between the Achaemenid Empire, Achaemenid Persian Empire under Xerxes I and an alliance of Polis, Greek city-states led by Sparta under Leonidas I. Lasting over the course of three days, it wa ...

, the 2nd Panzer Division entered Athens together with the 6th Mountain Division. At the end of the campaign the 2nd Panzer Division returned to Vienna for refitting, with parts of the division transported by sea and suffering heavy losses when the transport ships ''Marburg'' and ''Kybfels'' hits mines (laid by HMS ''Abdiel'') and sank.

Invasion of the Soviet Union

In October 1941, the 2nd Panzer Division was sent to the Eastern Front, reinforcing

in their push towards Moscow,

Operation Typhoon The Battle of Moscow was a military campaign that consisted of two periods of strategically significant fighting on a sector of the Eastern Front during World War II, between October 1941 and January 1942. The Soviet defensive effort frustrated H ...

. It was attached to the XL Panzer Corps (later to the V Army Corps of the

4th Panzer Army The 4th Panzer Army (), operating as Panzer Group 4 () from its formation on 15 February 1941 to 1 January 1942, was a German panzer formation during World War II. As a key armoured component of the Wehrmacht, the army took part in the crucial ...

during the

Battle of Moscow The Battle of Moscow was a military campaign that consisted of two periods of strategically significant fighting on a sector of the Eastern Front during World War II, between October 1941 and January 1942. The Soviet defensive effort frustrated H ...

). On November 16, the units of the division attacked the Soviet positions where "

Panfilov's Twenty-Eight Guardsmen The Panfilov Division's Twenty-Eight Guardsmen (), commonly referred to simply as Panfilov's Twenty-Eight Guardsmen, Panfilov's Men (, ''Panfilovtsy''), or just the Twenty-Eight, is a group of soldiers from the Red Army's 316th Rifle Division ...

" were supposed to be. The division retreated following a counterattack of the

Red Army The Workers' and Peasants' Red Army, often shortened to the Red Army, was the army and air force of the Russian Soviet Republic and, from 1922, the Soviet Union. The army was established in January 1918 by a decree of the Council of People ...

in the winter of 1941, taking part in various battles as a component in the 9th German Army during the first months of 1942. In 1943 the 2nd Panzer Division took part in

Operation Citadel Operation Citadel () was the German offensive operation in July 1943 against Soviet forces in the Kursk salient, proposed by Generalfeldmarschall Erich von Manstein during the Second World War on the Eastern Front that initiated the Battle of ...

, as part of the

XLVII Panzer Corps XLVII Panzer Corps (also: 47th Panzer Corps or XXXXVII. ''Panzerkorps'' or XXXXVII Panzer Corps) was a panzer corps of the German Army (Wehrmacht), German Army in World War II that was formerly designated as XLVII Corps. Various formations of the ...

of the 9th German Army of Army Group Centre. Following the operation's failure, the Red Army launched

Operation Kutuzov Operation Kutuzov was the first of the two counteroffensives launched by the Red Army as part of the Kursk Strategic Offensive Operation. It commenced on 12 July 1943, in the Central Russian Upland, against Army Group Center of the German ''Ger ...

in Army Group's Center's sector. The division retreated, suffering heavy losses, having also lost two of its three tank battalions earlier in 1942 when they were sent to the southern sector of the front to assist with the German push towards the Volga and Caucasus.Stoves, p. 20.

Battle of Normandy

In late 1943 the 2nd Panzer Division was sent to France for refitting after the heavy losses it suffered on the Eastern Front. The division was equipped with

Panther tank The Panther tank, officially ''Panzerkampfwagen V Panther'' (abbreviated Pz.Kpfw. V) with Sonderkraftfahrzeug, ordnance inventory designation: ''Sd.Kfz.'' 171, is a German medium tank of World War II. It was used in most European theatre of ...

s. Following the

invasion of Normandy Operation Overlord was the codename for the Battle of Normandy, the Allied operation that launched the successful liberation of German-occupied Western Europe during World War II. The operation was launched on 6 June 1944 ( D-Day) with the ...

, the division was moved to Normandy in June 1944; it engaged British troops of the 50th Infantry Division and the 7th Armoured Division. From June 6 until mid July the division stood in the Caumont area engaged in daily skirmishes with British units. During

Operation Epsom Operation Epsom, also known as the First Battle of the Odon, was a British offensive in the Second World War between 26 and 30 June 1944, during the Operation Overlord, Battle of Normandy. The offensive was intended to outflank and seize the ...

a group of six Panther tanks of the Pz.Rg.3 was used for a counterattack to take Cheux but that attack failed and five of their tanks were lost. Although the 2nd Panzer Division was very experienced the German doctrine overall was flawed and could not be exploited in Normandy. All German Panzer divisions in Normandy suffered severe defeats when counterattacking. The division was relieved at Caumont by the 326th Infantry Division and sent to the

Verrières ridge Verrières is the name or part of the name of several communes in France: * Verrières, Ardennes * Verrières, Aube * Verrières, Aveyron * Verrières, Charente * Verrières, Marne * Verrières, Orne * Verrières, Puy-de-Dôme * Verrières, ...

southwest of

Caen Caen (; ; ) is a Communes of France, commune inland from the northwestern coast of France. It is the Prefectures in France, prefecture of the Departments of France, department of Calvados (department), Calvados. The city proper has 105,512 inha ...

. During the Canadian

Operation Spring Operation Spring (July 25–27, 1944) was an offensive operation of the Second World War conducted by II Canadian Corps during the Normandy campaign in 1944. The plan was intended to create pressure on the German forces operating on the Britis ...

a Kampfgruppe from the division (Kampfgruppe Sterz) was sent to reinforce the 272nd Infantry division at St. Andre sur Orne and St. Martin. The Kampfgruppe took St. Martin, destroying The Black Watch in the process and got involved in street fighting in St. Andre sur Orne. Kampfgruppe Zollhöfer of the

9th SS Panzer Division The 9th SS Panzer Division "Hohenstaufen" () was a Waffen-SS armoured division of Nazi Germany during World War II. It participated in battles on both the Eastern and Western Fronts. The division was activated in December 1942. Many of the men ...

took over and struck towards Point 67. After Operation Spring 2nd Panzer was sent to the US sector to help in halting

Operation Cobra Operation Cobra was an offensive launched by the First United States Army under Lieutenant General Omar Bradley seven weeks after the D-Day landings, during the Normandy campaign of World War II. The intention was to take advantage of the dis ...

. They could stop the drive of the US 2nd Armored for a moment but were too weak to cover the whole front. The division retreated and with its last 25 tanks it took part in Operation Luttich, the failed German counterattack at Mortain. It was later encircled in the

Falaise pocket The Falaise pocket or battle of the Falaise pocket (; 12–21 August 1944) was the decisive engagement of the Battle of Normandy in the Second World War. Allied forces formed a pocket around Falaise, Calvados, in which German Army Group B, c ...

, but broke out with heavy losses in materiel and troops. At Falaise it was responsible for taking and holding St-Lambert-sur-Dive but was only able to take one part of the village. Nevertheless due to the efforts of the 2nd Panzer Division other German units, notably the 10th and the 12th SS, were able to cross the bridge over the Dives and escape eastwards. The division was reorganised in Germany, absorbing the depleted

352nd Infantry Division The 352nd Infantry Division () was an infantry division of the German Army during World War II. Deployed on the Western Front, the division defended Omaha Beach on D-Day, 6 June 1944. In late 1944, the division was reassembled as the 352nd Vol ...

. Due to the shortage in materiel, the division's complement of tanks was significantly reduced. Some tank companies only had

assault gun An assault gun (from , , meaning "assault gun") is a type of armored infantry support vehicle and self-propelled artillery, mounting an infantry support gun on a protected self-propelled chassis, intended for providing infantry with heavy di ...

s, although one battalion received Panther tanks.Mitcham, p. 48.

Battle of the Bulge

The division was sent to the Western Front and attached to XLVII Panzer Corps,

5th Panzer Army 5th Panzer Army () was the name of two different German armoured formations during World War II. The first of these was formed in 1942, during the North African campaign and surrendered to the Allies at Tunis in 1943. The army was re-formed in F ...

which was preparing for the German offensive in the Ardennes region of Belgium (the

in December 1944). On the eve of battle, 2nd Panzer was about full strength, with 27

Panzer IV The IV (Pz.Kpfw. IV), commonly known as the Panzer IV, is a German medium tank developed in the late 1930s and used extensively during the Second World War. Its ordnance inventory designation was Sd.Kfz. 161. The Panzer IV was the most numer ...

s, 58 Panthers, and 48 StuG III assault guns in the division tank parks. During the attack, 2nd Panzer drove towards the crucial road junction of

Bastogne Bastogne (; ; ; ) is a city and municipality of Wallonia located in the province of Luxembourg in the Ardennes, Belgium. The municipality consists of the following districts: Bastogne, Longvilly, Noville, Villers-la-Bonne-Eau, and Wardi ...

. However, Bastogne was quickly reinforced by the veteran

101st Airborne Division The 101st Airborne Division (Air Assault) ("Screaming Eagles") is a light infantry division (military), division of the United States Army that specializes in air assault military operation, operations. The 101st is designed to plan, coordinat ...

. Attacks against the town failed. On 18 December, in accordance with the original plan, 2nd Panzer was directed toward the Meuse River, but was unable to reach the Meuse, as American reinforcements threatened its flanks and supply line. Its vanguard got within 4 km from the Meuse, where on 24 December they were stopped by the U.S. 2nd Armored Division and the British

3rd Royal Tank Regiment The 3rd Royal Tank Regiment (3 RTR) was an armoured regiment of the British Army in existence from 1917 until 1992. It was part of the Royal Tank Regiment, itself part of the Royal Armoured Corps. It originally saw action as C Battalion, Tank Cor ...

. 2nd Panzer was forced to retreat by fierce American counterattacks and lack of petrol.

Battle of the Rhine

Now operating at an extremely reduced effectiveness, in the spring of 1945 the 2nd Panzer Division took part in the

Battle of the Rhineland The Siegfried Line campaign was a phase in the Western European campaign of World War II, which involved engagments near the German defensive Siegfried Line. This campaign spanned from the end of Operation Overlord and the push across northern ...

. In this, the Wehrmacht tried to halt the passage of the Allies across the River Rhine, and the division assisted as a component of the XIII Army Corps, of the 7th German Army, Heeresgruppe B. The final engagement of the unit was at the city of

Fulda Fulda () (historically in English called Fuld) is a city in Hesse, Germany; it is located on the river Fulda and is the administrative seat of the Fulda district (''Kreis''). In 1990, the city hosted the 30th Hessentag state festival. Histor ...

in April 1945. The division surrendered in

Saxony Saxony, officially the Free State of Saxony, is a landlocked state of Germany, bordering the states of Brandenburg, Saxony-Anhalt, Thuringia, and Bavaria, as well as the countries of Poland and the Czech Republic. Its capital is Dresden, and ...

and north-western Czechoslovakia to the US forces on 7 May 1945.

Commanders

The commanders of the division:Mitcham, p. 48–52. *Oberst

(Creation - 31 January 1938) *Generalleutnant

Rudolf Veiel Rudolf Veiel (10 December 1883 – 19 March 1956) was a German general ('' General der Panzertruppe'') during World War II. Career Veiel joined the army 1904, and was commissioned as an officer in 1905, serving in the Württemberg cavalry du ...

(1 February 1938 - 17 February 1942) *Generalleutnant

Hans-Karl Freiherr von Esebeck Hans-Karl Freiherr von Esebeck (10 July 1892 – 5 January 1955) was a German general who commanded the 15th Panzer Division in the Afrika Korps. Esebeck had knowledge of and was sympathetic to the anti-Hitler conspiracy in the military. He was ...

(17 February 1942 - 31 May 1942) *Generalmajor

Arno von Lenski Arno Ernst Max von Lenski (20 July 1893 – 4 October 1986) was a German military officer and general who served in the Imperial German army, the Wehrmacht of Nazi Germany, and after the war in the National People's Army of the German Democratic ...

(1 June 1942 - 30 June 1942) *Generalleutnant

(1 July 1942 - 10 August 1942) (Wounded) *Oberst (5 September 1942 - 30 September 1942) *Generalleutnant

Vollrath Lübbe Vollrath Lübbe (4 March 1894 – 4 April 1969) was a German general in the Wehrmacht. A veteran of World War I, he rose to command several divisions during World War II. He was a recipient of the Knight's Cross of the Iron Cross, awarded by Nazi ...

(1 October 1942 - 31 January 1944) *Generalleutnant

Heinrich Freiherr von Lüttwitz Heinrich Diepold Georg Freiherr von Lüttwitz (6 December 1896 – 9 October 1969) was a Prussian Junker, Olympic equestrian, and German officer who served in both World Wars, retiring as a ''General der Panzertruppe''. Lüttwitz's team competed a ...

(1 February 1944 - 4 May 1944) *Generalleutnant

Franz Westhoven __NOTOC__ Franz Westhoven (7 December 1894 – 9 October 1983) was a German general in the Wehrmacht during World War II who commanded several panzer divisions. He was a recipient of the Knight's Cross of the Iron Cross of Nazi Germany. Westhov ...

(5 May 1944 - 26 May 1944) *Generalleutnant

(27 May 1944 - 31 August 1944) *Oberst (1 September 1944 - 4 September 1944) *Generalmajor

Henning Schönfeld __NOTOC__ Henning Schönfeld (19 May 1894 – 11 March 1958) was a general in the Wehrmacht of Nazi Germany during World War II who commanded the 2nd Panzer Division. He was a recipient of the Knight's Cross of the Iron Cross. Awards and decorati ...

(5 September 1944 - 14 December 1944) *Generalmajor

Meinrad von Lauchert __NOTOC__ Meinrad von Lauchert (29 August 1905 – 4 December 1987) was a German general in the Wehrmacht of Nazi Germany during World War II. He was a recipient of the Knight's Cross of the Iron Cross with Oak Leaves. On the eve of the Battle ...

(15 December 1944 - 19 March 1945) *Generalmajor

Oskar Munzel __NOTOC__ Oskar Munzel (13 March 1899 – 1 January 1992) was a general in the Wehrmacht of Nazi Germany during World War II and in the Bundeswehr of West Germany who commanded several divisions. He was a recipient of the Knight's Cross of the I ...

(20 March 1945 - 3 April 1945) *Major i.G. Waldemar von Gazen (3 April 1945 - 4 April 1945) *Oberst Karl Stollbrock (4 April 1945 - 8 May 1945)

Organisation

The organisation of the division:

References

Bibliography

;Books * * * * * ;Websites * {{Subject bar , commons=y , commons-search=2nd Panzer Division (Germany) 0*02 Panzer divisions of the German Army in World War II German units in Normandy Military units and formations established in 1935 Military units and formations disestablished in 1945 Heinz Guderian