On the tranquil sea, a transport ship full of black coal mines is sailing slowly. The ship was carrying a large amount of heavy coal, and its speed could be described as crawling, and it moved cautiously, trying to send the cargo back to its homeland.

On the ship, a dozen crew members were drinking sake, and this kind of transportation work was already routine for them, and they had traveled back and forth on this route at least dozens of times in the course of a year, and they could not be more familiar.

The Sea of Japan is an important shipping route between China and Japan, and it is full of cargo ships between Japan and China between Yingkou and Fushun, some of which are carrying guns and ammunition produced in Japan to Northeast China, and some of which are carrying coal resources that Japan has looted from Northeast China and Shanxi.

These freighters traveled almost in a straight line every day, and this line was the lifeline of Japan's wartime and the most important transportation and supply route that sustained the industrial production of the Japanese Empire. Power generation, steelmaking, and all of these are coal-consuming industrial activities, and Japan's lack of oil has made it more dependent on coal than anyone thinks.

Another thing that caused Japan to run out of transportation capacity every day was food, and because most families in Japan had to take labor to participate in the war effort, food gradually began to rely on the occupation of grain production areas in China and South Asia for supply and supply. Add to that troop carriers and the occasional gunboat patrol boat, and the entire Sea of Japan is a busy scene.

The coal ship moved forward cautiously, because it was slightly overloaded, and the already small transport ship was extremely bulky. The Japanese sailors on board comfortably felt the sea breeze, tasted inferior sake, and felt the beauty of life.

"Ah...... If life could be so leisurely every day, maybe no woman would be happy. Taking a sip of sake with his mouth, a senior officer who was over half a hundred years old sighed to the captain beside him: "I heard that the war on the front line is already very unfavorable, have you ever thought about going to the battlefield?"

"No...... My family has been just fishermen for generations, and I am fortunate to have my own transport ship, which can be used to transport the military in wartime for free just to be exempted from military service, how can I go to such a dangerous place on the front line. The captain's family background is very good, and the painstaking management is not to serve on the front line and die, so naturally he will not take risks: "I am already loyal to His Majesty the Emperor, am I?"

"What about the front-line? You have some contact with the military, is there any latest news?" The first mate smiled bitterly, and after taking a sip of wine, he continued to ask: "I heard that the navy is ...... The army side is also not optimistic......"

"I heard that the base camp is sending more troops to Manchuria...... I haven't heard of any bad news about the war, and you know, the military has always been very strict with this kind of thing, and there is very little real news coming out. But since it's an increase in troops, it's not good news, right...... Who has ever heard of the fact that after winning a war, instead of hyping it up in the newspapers, they will send more troops to the front line? If you think about it, just the group of fools in the base camp would have been shouting about it a long time ago after winning the war, wouldn't they?

"Yes! If they win, even if it is only a small victory, they will brag about it and put gold on their faces......" The adjutant nodded after hearing this, and became even more lonely: "My second son is still in Manchuria...... I really don't know if this time will be more auspicious. ”

Suddenly, a sailor on duty ran into the cabin where a dozen people were resting, and shouted in a panic: "Hurry! Come on! We seem to see something terrible! Something big has happened! Captain! Captain!"

He shouted incoherently, and everyone could hear it inexplicably, and the captain stood up with a frown, waved his hand, and motioned for everyone to follow: "Go and see! See what has happened, and my sailors are so frightened that they can't even speak......"

So the group bypassed the iron staircase and walked up to the bridge, which was not very high, and immediately saw what they saw: lifebuoys floating in the sea, as well as some fragments of wooden decks, as well as some oil stains and other debris. There must have been a ship sunk here, and it was a Japanese ship - a lifebuoy with the name of a Japanese ship written on it, a transport ship called "Shichibanmaru".

"Nanabamaru? Nanabamaru, why is the name so familiar?" The captain thought for a long time, wanting to remember what kind of ship the sunken transport ship was. He was familiar with the name, but for a moment he couldn't think of where he had seen the transport.

"Nanabamaru? Didn't you see it once in Lushun? An army troop carrier, converted from a passenger ship, and you praised it that time and said that the ship was too big!" the first mate suddenly remembered the origin of the ship, and said to the captain.

But as if he had been caught in the throat by a fish bone, he found himself unable to utter another word: the sunken Nanabamaru troop transport was so huge that it was crowded with people who had left Japan or returned to Japan at any given time - and now that the ship had sunk, only Amakasu himself knew how many people had died.

"Strange!, why didn't you get a distress signal?" asked the captain as he looked at the sea suspiciously, and said to himself. He didn't expect anyone to answer his question, he just lamented that he had missed an opportunity to save someone.

But as if someone was deliberately trying to answer his question, he asked the self-talking question and saw something moving on the surface of the sea. The Japanese captain was stunned for a moment, then rubbed his eyes and looked again, and saw a white rolling wave, rapidly approaching his ship.

"Nani?" he narrowed, trying to see what the thing was that was speeding toward his ship. But when he saw what it was, he was instantly frightened and fell to the deck on the side of the ship.

"Fish...... Torpedo!" He pointed in the direction of the torpedo and turned back to his men and shouted loudly, but the torpedo apparently did not slow down by his shout, and after only two seconds, it crashed headlong into the side of the Japanese coal carrier.

"Boom!" The huge explosion suddenly broke the slightly overloaded Japanese transport ship into two, and then the Japanese ship sank to the bottom of the sea in an instant because of its own weight. After less than ten minutes, the sea was calm again, and there were still white sprays on the surface of the sea, and there were all kinds of messy debris floating around, and no one could see what had happened here.

......

"I say, captain, is it really okay for us to fight these unarmed ships that don't even have escort ships, and we have to record them and convert them into battle records?" asked a non-commissioned officer with a notepad who was recording the appearance of the sunken Japanese coal carrier, looking up to Captain Prien.

Moving from the heavily fortified Icelandic route and the east coast of the United States to the Far East, the German 20 submarines felt like they had once again come to heaven: they had never encountered such a relaxed hunting environment since they had changed their war zones countless times, attracted the attention of the Allies, and finally set up tight defenses and escort ships in various seas.

True, the German submarine commanders were going to fight in the waters of Japan, becoming "hunting". Because they found that Japan simply did not deploy enough anti-submarine forces in this sea area, or more intuitively, there were no Japanese anti-submarine destroyers in this sea area at all.

In the days since Prien and his partners sailed into the Sea of Japan, each submarine has achieved amazing results: they have sunk dozens of Japanese transports, including coal, people, and food. However, these Japanese ships, which were slow and loose-moving, simply did not take effective countermeasures.

The Japanese didn't even know what was going on, all they could do was have gunboats patrol the nearby waters and record what was going on. A few days passed, and the Japanese finally confirmed the existence of the German Navy's submarine forces, but they were still helpless against the German submarines, and even the number of the German Navy and the scope of its activities were not clearly summarized.

"It's really strange that these Japanese people have sunk ships nearby just a few hours ago, but there are still ships passing by here......," the sergeant noted the characteristics of the sunken coal carrier, while checking some photos of older Japanese ships, trying to find similar ships to sort them out.

"In any case, this is a very suitable area for submarine activities. Prien smiled and said to his first mate: "I don't know why the Americans didn't use their bases in the Far East to sneak attack the shipping lines of the Sea of Japan while the Soviet Union was still alive...... It's a good thing we came, otherwise it would have been a waste of such a pleasant place. ”

A catastrophe in the Sea of Japan has begun, and the Japanese base camp cannot believe that with a secret German submarine base in the Far East, 20 submarines can easily strangle Japan's fragile sea supply lines.

The whole of Japan was turned upside down, and every Japanese officer was anxious, looking at what was happening before them, and they did not know what to do -- Germany's strength left all those who knew about it without a very good solution, and it seemed that there was only one path left for Japan to choose: that is, to "defeat Germany."