On March 15, 1945, the British, French, Canadian and American forces gathered millions of troops again, 6 Canadian infantry divisions, 3 Canadian Air Force groups, the 5th Royal British Bomber Regiment, the 38th Air Service Regiment, the 19th and 58th Pacific Bomber Brigade, the 7th Dutch Bomber Group, the 9th Battalion, the 19th and 23rd Bomber Brigades of the British and Finnish ** bombers, forming a mixed coalition group, with the goal of bombing and destroying Sino-German positions, airfields, factories, and oil centers near Normandy.

The 1st Army, 3rd Army, 4th Army, 3rd Philippine Infantry Division, 11th Division, 1st Army, 3rd Army of the Philippine People's Army, 1st Turkish Army, 2nd Army, Israeli 5th Army, 7th Dutch Tank Regiment, 11th Regiment, 6 Infantry Divisions, 14th French Infantry Division, 17th Division, 34th Division, there are many troops, and more troops will be assembled one after another.

At 7:05 p.m., a piercing air raid siren suddenly sounded over the central English city of Coventry. At this time, the British Royal Air Force and the Nazi Air Force had been fighting fiercely over Britain for three months, and many cities in the British Isles, including the capital London, were under frequent air raids, so it was not surprising that air raid sirens sounded. But the strange thing is that the British domestic air defense system, which has always been able to give early warning of air strikes, did not evacuate the military, civilians and urban industries in time this time.

As a result, when the air raid sirens sounded, the residents of Coventry were unaware of the impending doom and continued to enjoy their lives as usual. Five minutes later, German "Heinkel 111" bombers flew over the city, and the bombing wave after wave lasted for 10 hours. With a huge explosion, Coventry was reduced to rubble. According to later statistics, 50,000 buildings were destroyed in Coventry, 50,000 shops were vandalized, 600 residents were killed, and 150 of their bodies were buried in the same cemetery because they were unrecognizable...... Coventry became the worst British city to be bombed in World War II. When British Prime Minister Winston Churchill learned the news, he was stunned at first, and then his face was full of anger and he remained silent. But people at that time did not know that Churchill had already learned of the German air raid on the city of Coventry, and after much deliberation, he finally decided not to take any defensive and diversion measures.

Although Nazi Germany's military ambitions for military expansion were clearly exposed, an atmosphere of pacifism permeated Britain after World War I. Chancellor Neville Chamberlain was a staunch appeaser, wishful thinking of Hitler going east to attack the Soviet Union, and for this purpose he connived at the German army's reoccupation of the Rhineland Demilitarized Zone, the annexation of Austria, and the forcible occupation of the Czech Sudetenland......

Only a few people, such as Churchill, have been attacking appeasement, saying that Hitler would bring disaster to Europe, urging Britain to rearm and encouraging its ally France to strengthen its military, pointing out that appeasement was "the complete surrender of Western democracies to the threat of Nazi force." But most people dismissed the warning as alarmist. In the end, the troubles could not be diverted eastward, and Germany took the lead in attacking Western Europe, and France quickly surrendered. Chamberlain was cornered, and Churchill, who had been vehemently opposed to appeasement, became the obvious choice for prime minister.

The victory of the Dunkirk evacuation did not mean that the British Isles were safe. Immediately afterwards, Germany was about to launch the "Sea Lion Project" to invade the British mainland. Prior to this, Germany planned to destroy the British air force first, and the Battle of Britain began. It was still a life-and-death battle for the British Empire.

And the first thing Churchill and his war chain of command must know is: how many tanks, planes, and submarines Germany will participate in the war, and what is its oil and steel production capacity.

Hitler was well aware of the importance of keeping secrets, and as early as 1934 he instructed the German military and intelligence to begin replacing the radio cipher system. In 1936, the German Intelligence Service introduced a new military code, which, unlike the previous manually-compiled codes, was compiled by machines. THE MACHINE IS APTLY CALLED "ENIGAMA", WHICH MEANS "ENIGMA" IN ENGLISH.

The "Enigma" is inexpensive, durable, and easy to operate, maintain and carry. What reassured Hitler even more was that whether the other party could get the "enigma" or not was irrelevant to the coded communication, because such a machine would be of no use to the captor without knowing the coded program.

Thus, Hitler's dependence on and trust in the "enigma" almost reached the level of superstition. He believed that it would be impossible for any country to decipher its code, so he did not hesitate to have the German navy, army, and air force all adopt the "enigma" cipher communication system.

The British took great pains to decipher it. They first followed the example of the Germans and built a machine that was like a "dumb riddle". However, it was far more difficult to get the coding system and coding program from the Germans than it was to build the machine, and the Germans kept it top secret, and even if the British succeeded, the Germans would quickly and easily replace it once they knew about it, and the programs and codes they had in their hands would be useless.

Jews, Poles "handed the sword"

The British Military Intelligence Agency has set up a code-breaking center at Bretchley Manor outside London. Here, hundreds of staff members were involved in deciphering top-secret intelligence on German military operations. And this manor and the deciphering work are also classified as top secret by the United Kingdom, and its code name is "super secret".

In 1938, when the British were clueless, a Jew revealed to British intelligence that he had been one of the designers of the "Enigma". The British, after careful screening, believed him. The Jew actually made a copy of an "Enigma" cipher machine, which, according to the British, was a miracle of imitation engineering, and it did the British a great favor.

However, in the summer and autumn of 1939, the Germans improved the original cipher machine, and the replica lost its effectiveness, and Britain was once again in trouble. But Polish intelligence came to the rescue of the British. As an ally of the British, the Poles handed over to the British the results of their years of research on the German cipher machine, as well as the new prototype of the cipher machine and the decryption machine.

Just a week later, Nazi troops marched into Poland. This touched the British codebreaker Knox, who said: "Poland's move is like an ancient knight handing his sword to his comrades before he falls." ”

In Bretchley Manor, in addition to Knox, a famous deciphering scholar, there is also a wizard in mathematics - Turing. A graduate of Cambridge University, he became one of the pioneers of the computer era after the war, relying on his research on cipher machines.

First, they began by developing a machine that could imitate or explain every "dumb riddle" of the Wehrmacht, so that they could introduce the coding routines that were often changed by all the German commands as they issued orders day and night, over the years. After a difficult struggle, the British finally made a machine with the above functions and named it "**".

At the end of 1939, the "**" deciphered the German code, and the British were ecstatic. From then on, the secret plans and plans of action of the German army continued to pass from Bretchley Manor to MI6 Colonel Menzies, and then directly to Churchill's desk. In fact, the vast majority of the actions of the German army during World War II could not be concealed from the British, but the British kept the intelligence sources under cover up very well and never aroused the suspicion of their opponents.

On July 2, 1940, Hitler released the first set of "Sea Lion" battle plans, that is, the British landing operation plan. As soon as the campaign began, Churchill and the Air Staff learned most – and sometimes all – of the Luftwaffe's plans through "super-secrets".

In response to the command of the commander of the Luftwaffe Goering, who demanded the seizure of air supremacy, the British Royal Air Force formulated a plan to concentrate superior forces to strike at the enemy. Since the British Air Force did not have as many planes as Germany, it could only concentrate fighter squadrons and main defensive forces at the right time, in the right place, and at the right altitude to deal with the enemy's main attacking force. Relying on early warning radar and deciphered German military intelligence, the RAF was able to accurately take to the air to intercept the arrival of the Nazi Air Force, without the need to patrol in time and space to guard against German surprise attacks—thus greatly reducing the physical exertion of pilots and the consumption of strategic materials such as gasoline.

On August 13, 1940, over Sussex and Kent, a group of 80 German "Dornier 17" bombers, and an even larger number of "Junker 88" dive bombers, flew to the heart of Britain and the coastline to carry out bombing missions. Due to the thick clouds in the sky, the German escort fighters could not take off as planned, and the bombers had to strike alone.

The British Air Force command was aware of the German plan of action in advance, and as soon as the German aircraft was spotted on the radar, the combat plan that had already been prepared was immediately activated...... In this encounter, the Luftwaffe lost a total of 47 aircraft and more than 80 were damaged, while the British Air Force lost only 13 aircraft.

Earlier, Goering boasted to Hitler that the air defense in the south of Britain would collapse in four days, and the British Air Force would be expelled from the skies over Britain in four weeks. Although Germany achieved some success in the subsequent bombings, relying on radar and code-breaking, the British Air Force fought a disparity of 1:3 in combat power, and after two months of fierce battles, Goering's boastful sea mouth became a dream: because Goering never obtained air supremacy over Britain and the English Channel, Hitler had to announce that the "Sea Lion Plan" was postponed indefinitely.

Save the city or save the country?

In the meantime, Germany has not discovered the key reason for the defeat: the "mystery" has been grasped by the British. It wasn't until the repeated defeats in the Battle of Britain that Hitler finally began to doubt whether the "Enigma" was still safe, so he ordered the German army to prepare for an air raid test.

On November 12, 1940, the command was conveyed by the Luftwaffe command to the Luftwaffe group stationed in Western Europe: 500 aircraft were dispatched in 48 hours, 4,500 *** were dropped on Coventry, and the operation was codenamed "Moonlight Sonata". In addition to verifying the secrecy of the "Enigma", the plan also had the purpose of bombing Coventry, a major British industrial city, in order to destroy the British resistance.

The British "**" quickly deciphered the information, and Knox handed it to Colonel Menzies with trembling hands, Coventry was Knox's hometown, where his wife and children were located. The information was then immediately sent to Churchill.

Just 90 miles from London, Coventry is an ancient city with over 900 years of history, a city of 250,000 inhabitants and numerous heritage sites, and is home to one of Britain's major arsenals and a centre for aircraft and car manufacturing. The Germans threw 4,500 ***, enough to wipe this beautiful ancient city off the face of the earth.

After reading the book, Churchill immediately felt that the matter was difficult, and immediately notified the military and political heads to hold a meeting in the underground war room of the Prime Minister's Palace.

Menzies, in accordance with Churchill's instructions, first read out the intercepted information, and the whole battle plan of the Germans was clear: the number of planes put into battle, the predetermined tactics, and even the reasons why Hitler launched the operation.

It was easy to save Coventry: at that time, Britain had 410 mobile anti-aircraft guns at its disposal, and it was completely possible to use these anti-aircraft guns to strengthen Coventry's anti-aircraft defense, and the air force proposed to set up an interception line in the English Channel to block the invasion of German aircraft; The Ministry of Civil Protection, on the other hand, believes that it is possible to raise an alert in advance to evacuate residents and move valuable property to minimize damage. The special forces thought even more: send commandos to the Brittany airfield to assassinate the fighter pilots who led the bombing. If they were all implemented, Coventry's losses would undoubtedly be greatly reduced.

But Churchill feared that by saving Coventry, the secret that the British had deciphered the German cipher "mystery" would be exposed. You can only choose one of the two, which is more important? Churchill was caught in the long test. Eventually, he snuffed out his cigar and stood up: Coventry had to be sacrificed to protect "super secrets". While making a decision, he moved with emotion, and the corners of his eyes moistened a little: "The price of sacrificing a city is a little bigger, but compared to the whole of Great Britain, it is nothing?" ”