Question: When did the Germans mount a large-scale offensive against the Soviet Union called Case Blue?
About the article "Operation Barbarossa", section "Aftermath".

Candidate passages:
With the failure of the Battle of Moscow, all German plans of a quick defeat of the Soviet Union had to be revised.
The Soviet counteroffensives in the winter of 1941 caused heavy casualties on both sides, but ultimately eliminated the German threat to Moscow.
Nevertheless, despite this setback, the Soviet Union had suffered heavily from the loss of large parts of its army, allowing the Germans to mount another large-scale offensive in the summer of 1942, called Case Blue, now directed towards the oil fields of Baku.
This offensive failed just as "Barbarossa" had: the Germans again conquered vast amounts of no-mans-land, but they had again failed to achieve their ultimate goals when they were defeated at Stalingrad.
By then, the Soviet war economy was fully operational, so the Soviet Union was able to simply outproduce the Germans, who were not prepared for a long war of attrition.
As a result, the Germans' last all-out offensive in 1943 at the battle of Kursk failed.
After three years of constant warfare, the Germans were exhausted; thus the Soviets were finally able to defeat the Germans decisively in Operation "Bagration" during the summer of 1944.
This led to a chain of Soviet victories which pushed the Germans back to Berlin in just one year, leading to the surrender of Germany on 8 May 1945.
The Eastern Front of World War II was fought between Germany and her allies against the Soviet Union.
The front began on 22 June 1941 with Operation Barbarossa, where Germany launched a massive invasion of the Soviet Union.
Using their highly advanced Blitzkrieg doctrine and spearheaded by formidable Panzer armies, the Germans pushed deep into the Soviet Union, while inflicting enormous losses on the Red Army.
During the Battles of Smolensk and Kiev, the Red Army lost and suffered heavy casualties, but managed to delay the German advance, thus giving more time for defenses and fortifications to be built around Moscow.
By October Germany reached the gates of the Soviet capital and Hitler launched Operation Typhoon, to capture Moscow before winter.
However due to stiff Soviet resistance and Vyazma and Tula, the fast moving panzer armies were slowed considerably.
An unusually cold winter began, stopping the German tanks dead in their tracks only 15 miles away from Moscow and allowing the Red Army to launch a massive counter-offensive which pushed the Germans to a safe distance away from city.
The Soviets had defended their capital city, but at a very high cost.
The Red Army suffered more than 1,280,000 casualties.
In the north the Germans besieged Leningrad but the Red Army kept them at bay.
This siege would last three years.
Even though the Soviets had won at Moscow, the war was far from over.
Germany occupied vast areas of the country and was still strong.
In the summer of 1942, Hitler launched Case Blue, a massive offensive to capture the Caucasus.
The Germans captured key cities such as Rostov, Kharkov and Krasnodar and pushed towards a key transport hub on the Volga, Stalingrad.
The German 6th Army entered the outskirts of the city in August but was slowed down with fierce Soviet resistance.
Even though the Germans controlled 90% of the city, they were unable to dislodge the last Soviet defenders tenaciously holding on to the west bank of the Volga.
Winter set in and the German tanks were once again unable to perform well.
In November the Red Army launched Operation Uranus, another massive counter-offensive which destroyed the weak Romanian and Hungarian armies and encircled the Germans inside Stalingrad.
The now depleted German Army held on against wave after wave of Soviet attacks until they finally collapsed and surrendered on 3 February 1943.
With more than 1.7 million casualties, the Battle of Stalingrad was the bloodiest in history.
With Stalingrad secure the Red Army launched Operation Little Saturn and pushed the Germans back into the Ukraine.
In the summer of 1943, Hitler launched yet another offensive, Operation Citadel.
Two large Panzer Armies spearheaded the attack in a pincer movement to encircle the industrial city of Kursk.
However thousands of Soviet T-34 tanks were rushed to Kursk and engaged the German Panzer and Tiger tanks in the largest tank battle in history, just outside the city resulting in another decisive victory for the Red Army.
After Kursk, the Germans had suffered heavy casualties and their supplies had grown thin, while the ever growing Red Army had a never ending flow of supplies and troops.
Germany hadn’t expected the war to last this long and were beginning to fall apart.
By spring of 1944, the Red Army had relieved Leningrad and pushed the Germans out of Russia and the Ukraine.
Army group Center however, still held on strong and occupied most of Byelorussia.
During this time, the western Allies had invaded northern France and forced Germany to relocate some troops and supplies to the west.
This allowed the Soviets to launch Operation Bagration, the largest Soviet offensive of the war which destroyed Army Group Center and had the Red Army advance to the border of Prussia and Poland.
In the south the Red Army overran Romania and was pushing into Hungary.
Now with the Germans fighting the Americans and British in the west and the Soviets in the east, the fall of Germany was all but inevitable.
The next Soviet offensives came in the winter of 1945, the Vistula-Oder Offensive and the East Prussian Offensive in which the Red Army smashed through German occupied Poland and captured the historical capital of Germany, Konigsberg.
In the south the Red Army pushed into Hungary and captured Budapest, thus knocking Hungary out of the war.
By the end of March the Red Army had invaded Germany and had advanced to the Oder River, just 50 miles east of Berlin.
As Germany’s end neared close the Soviet Union now looked to capture key cities in central Europe, before the fast moving American armies from the west did.
The Red Army then turned some of its attention to advance and capture Vienna and Prague.
In mid April 1945, the Red Army launched its final offensive, the Berlin Offensive.
After nearly two weeks of fighting, the Red Army captured Berlin and shortly after Germany surrendered. 
Due to the significant initial successes of the 1942 German summer offensive, the German command and especially Hitler expanded the already sophisticated plan even more, putting great strain on their forces.
Hitler did not expect the Soviets to be able to launch a counteroffensive on the scale of Operation Uranus, and therefore deployed valuable units elsewhere on the front, while ordering the "Wehrmacht" to simultaneously strive for numerous goals.
Any opposition to his fluctuating plans simply led to dismissal by Hitler, who interfered more and more in the command process.
Overstretched by the vast area they had captured, the reduced capabilities of the "Heer" and its allies to defend this territory enabled the Soviets to mount a decisive offensive at Stalingrad, encircling a whole German army.
Soon both sides concentrated largely on the epic struggle for the city, making the Caucasus campaign a secondary theatre.
With Army Group B unable to hold the Volga line, subsequent Soviet operations threatened to cut off Army Group A in the Caucasus, and it was forced to withdraw.
The surrender of Sixth Army was a serious blow to German morale in general and it proved a personal shock to Hitler.
Nevertheless, despite the destruction of Sixth Army, the Soviets only caused the "Heer" to retreat from their advance towards the Caucasus, further delaying the final decision on the Eastern Front.
The by now highly confident Soviet command overestimated its capabilities and pushed its forces deep into the German lines, to the limit of its supply lines, which led to a severe defeat at Kharkov and gave the Germans the opportunity to mount another large strategic offensive. 
The Soviet Union demanded to move the Finnish border further away from Leningrad.
The USSR also insisted that Finland lease the Hanko Peninsula (or similar territory at the entrance to the Gulf of Finland) for the creation of a Red Baltic Fleet naval base.
However, Finland refused and the Soviet Union invaded the country, initiating the Winter War.
The USSR set up the Finnish Democratic Republic (), a short-lived Soviet puppet regime in the occupied Karelian territories.
The Soviets also occupied the Petsamo municipality in the Barents Sea coast during the war.
The Moscow Peace Treaty ended the state of occupation on 12 March 1940, as Finland was forced to cede parts of Karelia.
The land accounted for 9% of the country's territory, included Finland's second largest city Viipuri and much of Finland's industry.
About 422,000 Karelians — 12% of Finland's population — choose rather to evacuate beyond the new border and lose their homes than to become Soviet subjects.
The military troops and the remaining civilians were hastily evacuated.
Finland also had to cede a part of the Salla area, the Kalastajansaarento peninsula in the Barents Sea and four islands in the Gulf of Finland.
The ceded areas were integrated within the Karelian ASSR to form the Karelo-Finnish SSR.
When the hostilities resumed in 1941, Finnish forces retook the lost areas and then advanced further up to the Svir River and Lake Onega before the end of the year.
In the Soviet offensive of 1944 against the Finns the Red Army advance was halted by the Finns before reaching the 1940 border or, in the sole case where it did happen, the Red Army was promptly thrown back in Finnish counterattack.
In the negotiations that followed the stopping of the Soviet offensive Finns further ceded the Petsamo municipality to the Soviet Union in the Moscow Armistice.
The Soviet forces took the municipality from the Germans during the Petsamo–Kirkenes Offensive. 
Operation Barbarossa (German: "Fall Barbarossa", literally "Case Barbarossa"), beginning 22 June 1941, was the code name for Germany's invasion of the Soviet Union during World War II.
Over the course of the operation, about four million soldiers of the Axis powers invaded the USSR along a front, the largest invasion in the history of warfare.
In addition to troops, "Barbarossa" used 600,000 motor vehicles and 750,000 horses.
The ambitious operation was driven by Adolf Hitler's persistent desire to conquer the Soviet territories as embodied in "Generalplan Ost".
It marked the beginning of the pivotal phase in deciding the victors of the war.
The German invasion of the Soviet Union caused a high rate of fatalities: 95% of all German Army casualties that occurred from 1941 to 1944, and 65% of all Allied military casualties from the entire war.
Operation "Barbarossa" was named after Frederick Barbarossa, the medieval Holy Roman Emperor.
The invasion was authorized by Hitler on 18 December 1940 (Directive No.
21) for a start date of 15 May 1941, but this would not be met, and instead the invasion began on 22 June 1941.
Tactically, the Germans won resounding victories and occupied some of the most important economic areas of the Soviet Union, mainly in Ukraine.
Despite these successes, the German offensive stalled on the outskirts of Moscow and was then pushed back by a Soviet counter offensive without having taken the city.
The Germans could never again mount a simultaneous offensive along the entire strategic Soviet–German front.
The Red Army repelled the "Wehrmacht"s strongest blow, and Adolf Hitler did not achieve the expected victory, but the Soviet Union's situation remained dire.
Operation "Barbarossa"s failure led to Hitler's demands for further operations inside the USSR, all of which eventually failed, such as continuing the Siege of Leningrad, Operation Nordlicht, and Operation Blue, among other battles on occupied Soviet territory.
Operation "Barbarossa" was the largest military operation in history in both manpower and casualties.
Its failure was a turning point in the Third Reich's fortunes.
Most importantly, Operation "Barbarossa" opened up the Eastern Front, to which more forces were committed than in any other theater of war in world history.
Regions covered by the operation became the site of some of the largest battles, deadliest atrocities, highest casualties, and most horrific conditions for Soviets and Germans alike—all of which influenced the course of both World War II and 20th-century history.
The German forces captured over three million Soviet POWs in 1941, who were not granted the protection stipulated in the Geneva Conventions.
Most of them never returned alive.
Germany deliberately starved the prisoners to death as part of its "Hunger Plan", i.e., the program to reduce the Eastern European population.