While the fighting was raging in Warsaw, the German troops on the Ukrainian side were resting and recuperating and encircling and suppressing the Russian stragglers scattered in Western Ukraine.

The organization of these Russian troops is basically zero, but after all, there are guns and ammunition, and it is obviously not a good idea to let them wander around like bandits. As a result, the German infantry and armored hunters began to sweep away the remnants of the enemy from area to area, which made the Germans have a longer recuperation break than planned.

By 18 July, the Germans, who had stopped attacking for two weeks, were finally back on the offensive, with Army Group B's main assault group advancing southeast along the Dnieper River, while the 10th Army, newly assigned to Army Group B, was attacking from southwestern Ukraine toward Mykolaiv and other cities. Only half of the 10th Army's units were mechanized, and the rest of the general forces were semi-mechanized traditional infantry, so the pace of advance was much less than that of mechanized assault clusters.

Fortunately, at this time, the number of Russian troops in southern Ukraine was not large, and they were all frightened by the previous German army's triumphant advance, and they were extremely lacking in the desire to fight.

But the elite assault group of Army B, which was attacking along the Dnieper towards the Donbass coal mining area, ran into Cossack units transferred from the Don region and met with extremely determined resistance.

By the time the 10th Army occupied Odessa, drinking the Black Sea, Guderian had just arrived under the city of Dnepropetrovsk.

The siege lasted three days, during which the Tenth Army advanced almost a hundred kilometers east along the coast of the Black Sea, and in a telegram to the command of Army Group B claimed that its artillery could already reach the mouth of the Dnieper.

By 28 July, all Ukrainian territory west of the Dnieper River had been occupied by the Germans.

On 30 July, Romania began supplying fuel to the German army in Ukraine via the Guò land route, in accordance with its secret agreement with Germany.

As a result, the supply lines of the German army were greatly shortened, and the supply of oil became abundant.

Then Guderian's assault group again forced its way across the Dnieper and rushed towards the Donbass coal mines.

The 10th Army, on the other hand, crossed the widest section of the Dnieper without resistance and swaggered towards the Isthmus of Perekop.

The Crimean Peninsula is crucial for the supremacy of the Black Sea, and the capture of the peninsula can control the Kerch Strait and block the passage between the Sea of Azov and the Black Sea, while the fleet in Sevastopol can control the Gulf of Kalkinit, and almost the entire coast of Ukraine will be threatened by the fleet deployed in Sevastopol.

Tsarist Russia fought many times for the Crimea and Ottoman Turkey, and this peninsula can be said to be an integral part of Russia's Balkan strategy.

In addition, the peninsula's ease of defense and difficulty in attacking also makes the peninsula extremely militarily valuable.

To attack the Crimean Peninsula, it is necessary to pass through two isthmuses, one large and one small, the narrower Isthmus of Perekop, sandwiched between Lake Sivash and the Black Sea, only eight kilometers wide, and a considerable part of these eight kilometers is impassable swampy terrain.

After the Isthmus of Perekop, you have to pass through a wide isthmus, which is dotted with several small lakes, in short, it is also a headache.

However, after breaking through these two isthmus, the entire Crimean Peninsula will be undefendable, and the dry and vast steppe is simply for the armored troops to gallop freely.

The Tenth Army came to the Isthmus of Perekop on 3 August, while several Russian divisions were already fortified on the isthmus, preparing to resist the German invasion of the Crimean Peninsula.

In the early morning of 8 August, after four days of preparation, the Germans began shelling the Russian troops defending at the isthmus, and the artillery preparation lasted for three hours, and after the day was completely bright, the 56th Army of the Tenth Army began to attack the Russian defenders on the isthmus.

The most tragic battle of the war queens since the beginning broke out on the narrow isthmus, the tenth army lacked armored troops, so in order to ensure the breakthrough of the isthmus, a large number of war queens were invested, and the Russian army invested two brigades of war queens to try to hold the isthmus with the help of the strength of the war queens, so the two sides totaled more than 400 battle queens on the isthmus and shot at each other on the open ground with almost no line of sight.

At this time, the scene on the isthmus is almost like a time gone back in time, and the battle queens of both sides line up in a neat horizontal line and open fire, very much like the battle of guns in the Napoleonic era.

The battle continued throughout the day, with comparable casualties.

After the fierce fighting of the day, the 10th Army continued to launch a night attack with its troops, and the Germans who attacked at night occupied some Russian positions at one point, but as dawn came, the Russians recaptured these positions with a ferocious counterattack.

After daybreak, the Germans attacked again, this time with strong air support from the Luftwaffe, and the bombs dropped by lightning dive bombers fell on the Russian positions one after another, overturning one strong pillbox after another to the ground.

But on this day, the Germans made only a small amount of progress, they made a bridgehead embedded in the Russian position near the swamp that the Russians called "lazy cancer" oh not "lazy sea", and the reserves of the 56th Army quickly entered the bridgehead to strengthen the defense, and smoothly blocked the night attack launched by the Russian army that night.

The next night, the situation was extremely chaotic, the Russian army wanted to take the bridgehead occupied by the Germans during the day with a night attack, and the Germans wanted to open up the situation with a night attack, but the night attack troops on both sides met in the night, and it turned out to be a pot of porridge, and no one knew what was going on, just opened fire on everyone who didn't look like a friendly army.

After dawn on the third day, the situation stabilized, and both sides did not bother to care whether it was friendly or enemy forces that were fighting at night.

On the third day, the Russian army began to be unable to support it, after all, the German troops were in wheel warfare, and the Russian army was busy defending against the sharp knife that stabbed at the Donbas coal mining area, and the army that could continue to reinforce the Crimean Peninsula was limited, coupled with the fact that the Luftwaffe continued to sink transport ships on the Sea of Azov, which greatly reduced the transportation capacity of the Russian army, so on the third day, the situation of the Russian army guarding the Perekop Isthmus became worse and worse.

On the fourth day, the Russian army began to retreat, the Tenth Army failed to detect the movement of the Russian army in time, and by the time the Tenth Army began to pursue, most of the Russian army had already retreated to the defensive zone on the second isthmus.

But the second isthmus is much wider than the Perekop isthmus, and there are not as many difficult swamps and saline lands as it can be walked on.

On 15 August, the 10th Army entered the Crimean Peninsula, and immediately after the command of Army Group B, the 30th New Panzer Division was transferred from the reserve to cross the Perekop Isthmus to join the occupation of the Crimean Peninsula.

On August 25, only the Kerch Peninsula in the east and the Sevastopol fortress, the headquarters of the Black Sea Fleet, in the west, remained unconquered by the Germans.