The basement of building one at Pearl Harbor reeks of sweat, cigarette smoke, and desperation. It’s April 18th, 1942, and Commander Joseph Rofort paces between rows of cramped desks where exhausted Navy crypt analysts hunch over sheets covered in five-digit number groups. Every man in this room knows they’re losing the war. The Japanese naval code JN25 sits before them like an impenetrable fortress. For 18 months, America’s best mathematicians have thrown themselves against this cipher. And for 18 months, they failed.

The numbers mock them. 35 33 possible code groups. Each one representing a word, a phrase, a ship name, or a location. Even if you crack the code groups, they’re then disguised by additive tables that change every few weeks. It’s a code wrapped inside a cipher, and it’s killing American sailors. In the four months since Pearl Harbor, Japanese forces have steamrolled across the Pacific. Wake Island fallen. Guam fallen. The Philippines on the verge of collapse. American submarines hunt blindly through empty ocean while Japanese carriers strike with surgical precision.

The kill ratio is devastating. For every Japanese ship sunk, America loses three. Admiral Nimttz needs to know where the enemy fleet will strike next. But the intelligence officers can only shrug and point to vast stretches of blue on the map. What Rofort doesn’t know, what nobody in that basement knows on this humid Hawaiian morning, is that the breakthrough they desperately need will come from the most unlikely source imaginable. Not from a Yale mathematician or a Naval Academy graduate, not from one of the Japanese language experts imported from California universities.

The solution will come from a kid who shouldn’t even be in the building. a 17-year-old who lied his way into the Navy with a forged birth certificate and a voice that keeps cracking at the worst possible moments. His name is Andrew Mate Gleason. And in 6 weeks, his obsessive tinkering with what everyone else dismisses as noise, will unlock JN25. His method will expose the location of the Japanese fleet, enable America’s greatest naval victory, and save thousands of American lives.

But first, he has to convince a room full of officers that a teenager with no formal training in cryptography has spotted something that the experts have been missing for over a year. The clock is ticking. The Japanese are planning something big, and nobody’s listening to the kid. To understand why JN25 seemed unbreakable, you have to understand its terrifying elegance. The Japanese Navy introduced this cipher system on June 1st, 1939. Specifically designed to resist Western crypton analysis. Unlike simpler codes that substitute letters for letters, JN25 operates in two brutal stages.

First, Japanese messages are encoded using a massive code book containing 33 five-digit code groups. The word battleship might become 15347. Tomorrow might be 90 horn, location, names, ship designations, operational commands, all converted to anonymous numbers. Even if you intercept a message, you’re staring at strings like 153472891-442139876 that mean absolutely nothing without the code book. But the Japanese didn’t stop there. They knew that if Americans captured one of their code books, which happened in December 1940 when the British seized German papers from a captured ship, the entire system would collapse.

So they added a second layer, additive encryption. Before transmission, operators add random five-digit numbers from separate additive tables to each code group. Now 15347 becomes 4M92 or 9134 or any of billions of possible combinations. And those additive tables changed every few weeks, sometimes every few days. The numbers are devastating. Even with captured equipment and 6 months of messages, Agnes Driscoll, the Navy’s legendary Madame X, who had broken previous Japanese codes, made virtually no progress. By early 1942, OP20G could read perhaps 1% of intercepted JN25 traffic, and most of that was old news about past operations.

The messages that mattered, current fleet movements, upcoming attacks, remained opaque. The experts had tried everything. They’d built frequency analysis tables, attempted statistical attacks, looked for repeated patterns in thousands of messages. Mathematicians from Princeton and Yale worked 16-hour shifts. Nothing worked. The additive tables scrambled everything. It was like trying to solve a jigsaw puzzle where the pieces kept changing shape. Admiral Ernest King, commanderin-chief of the US fleet, was losing patience. Gentlemen, he told naval intelligence officers in March 1942, “The Japanese are running circles around us.

They know where our ships are. We don’t know where theirs are. This cannot continue.” But nobody had answers. The Office of Naval Intelligence estimated it would take another 2 years to make meaningful progress on JN25, assuming they could recruit 50 more crypists and double their computing resources. 2 years. By then, the war might be lost. Japanese strategists were already planning their next major offensive, a strike that would either knock America out of the Pacific or draw the US Navy into a decisive trap.

Those plans were being transmitted daily in JN25 traffic. The messages flowed through the airwaves, captured by listening stations from Hawaii to Australia. Boxes of intercepted transmissions piled up in building one at Pearl Harbor. and they might as well have been written in ancient Samrian. The stakes extended beyond military defeat. Every day the code remained unbroken. American submarines hunted blindly. Transport convoys sailed without knowing Japanese carrier positions. Commanders made decisions based on guesswork. Men died because America was fighting deaf and blind.

Captain Lawrence Safford, the father of Navy crypt analysis, told colleagues that breaking JN25 might be mathematically impossible. The problem space was simply too large. We’re looking for patterns in pure randomness, he said. The additives ensure we’ll never see the same encryption twice. Even if we had infinite time and infinite computing power, there’s no guarantee we’d break it. into this atmosphere of defeat and exhaustion stumbled a kid from Fresno, California, who wasn’t supposed to be there, who had no business wearing that uniform, and who was about to prove all the experts catastrophically wrong.

Andrew Mate Gleason was born November 4th, 1921 in Fresno, California to a botonist father and a Swiss American mother. He should have been starting college. Instead, on December 8th, 1941, one day after Pearl Harbor, he stood in front of a Navy recruiting officer with a forged birth certificate, claiming he was 19 years old. He was 17. His voice hadn’t fully deepened. He barely needed to shave. “You’re kind of skinny, kid,” the recruiter said, looking him over. “You sure you want this?” Andrew wanted it desperately, not from patriotism alone, though that burned in him.

He wanted it because he was bored. Crushingly, devastatingly bored. He’d graduated Roosevelt High School in Yonkers a year early, spent a restless year doing odd jobs, and discovered he had a peculiar talent that nobody seemed to value. He could see patterns in chaos. Give him a page of numbers, a broken machine, a scattered puzzle, and his mind would automatically start organizing it, finding the hidden structure. His father thought he should go to college. His mother wanted him to wait until he was older, but Andrew had watched news reels of burning ships at Pearl Harbor, and something in him snapped into focus.

This was real. This mattered. This was a puzzle worth solving. The Navy, desperate for bodies, didn’t look too closely at his birth certificate. By January 1942, Seaman apprentice Gleason was assigned to OP20G, the Navy’s crypt analysis division, not because of any special qualifications, but because he’d mentioned on his intake form that he liked math and puzzles. That was enough. They needed everyone they could get. He arrived at the Nebraska Avenue complex in Washington DC on February 3rd, 1942.

A babyfaced kid in an ill-fitting uniform walking into a building full of Naval Academy graduates and Ivy League mathematicians. Commander Howard Angstrom took one look at him inside. They’re sending us children now. I’m 19, sir. Andrew lied automatically. Sure you are. Can you type? Yes, sir. Good. You’ll work message sorting 10-hour shifts. Don’t touch anything important. Don’t bother the real cryp analysts. Just sort the intercepts by frequency and date. Think you can handle that without screwing it up?

Andrew nodded. It wasn’t what he’d imagined. He’d pictured himself heroically breaking codes like the adventure cals, but it was a start. For two months, he sorted messages, thousands of them, five-digit groups, endless and meaningless. He wasn’t allowed to work on actual crypt analysis. He didn’t have the credentials, the training, or the rank. He just sorted and filed and tried not to be noticed. But Andrew Gleason had a problem. He couldn’t not notice patterns. It was like telling him not to breathe.

As he sorted those messages day after day, his mind kept cataloging inconsistencies, little things that didn’t quite fit. And late at night, alone in his barracks, he started writing them down in a notebook he wasn’t supposed to have. He was about to stumble onto something that would change everything. And when he tried to report it, they’d tell him to shut up and get back to filing. April 1942. Andrew Gleason has been sorting messages for 10 weeks when he notices something impossible.

It’s 2:00 a.m. and he’s supposed to be asleep, but instead he’s in the crypt analysis room with permission from the night duty officer, a young enen who doesn’t care what the kid does as long as he doesn’t bother anyone. Andrew spreads out 60 intercepted messages across an empty desk. They are all from the same Japanese transmission station, all sent during March. Standard procedure says you look for repeated code groups. The same fivedigit number appearing in multiple messages might be a common word like the or attack.

But additive encryption should make that impossible. The additives should randomize everything. Except Andrew’s been noticing that certain messages sent from Tokyo to Berlin have letter indicators, metadata at the beginning of the transmission that only use the first 13 letters of the alphabet. And messages from Berlin to Tokyo only use the last 13 letters. It’s barely noticeable. Nobody’s mentioned it in any of the analysis reports he’s filed. He grabs a pencil. What if, and this seems crazy, what if the unencrypted indicators follow the same pattern?

What if Tokyo to Berlin headers use only A through M in plain text and Berlin to Tokyo uses N through zed? If that’s true, and if you know the plain text structure of the indicators, you could subtract the plain text from the encrypted indicator to recover part of the additive table. And if you have part of the additive table, you can start peeling back the encryption on the actual message content. Andrew works through the math. His hands shake slightly.

It’s such a stupid simple idea. Surely the real cryp analysts have thought of this, but he checks the analysis logs. Nothing. Nobody’s following this thread. By 5 a.m., he’s tested his hypothesis on five messages. It works. He can recover indicator additives with 73% accuracy. His crude method, just pencil and paper, has given him a foothold into the supposedly unbreakable additive system. He needs to tell someone. But who? He’s a kid. A message sorder. The actual cryp analysts barely acknowledge his existence.

Marshall Hall Jr., One of the lead mathematicians once told him, “Son, you’re here to file papers, not to play codereaker.” Andrew approaches Lieutenant Commander Howard Angstrom during the morning shift change. Sir, I think I found something in the JN25 traffic. The indicator headers might be, “Not now, Gleason. We’re busy.” But sir, if we know the plain text structure of the Gleon, I’m going to say this once. You’ve been here 10 weeks. Agnes Driscoll has been breaking codes since before you were born.

Joe Rofort fought in the First World War. We have Yale mathematicians and Naval Academy cryptographers working 16-hour days on this. Do you seriously think you’ve spotted something they’ve all missed? I maybe I have the math I can show. That’s enough. Get back to message sorting. That’s your job. Do your job. Andrew returns to his desk, notebook in hand. The breakthrough sits there, 73% validated, and nobody wants to hear it. In his notes, he writes, “They think I’m too young to matter.

Maybe I am, but the math doesn’t care how old I am.” For 3 weeks, Andrew Gleason keeps his discovery to himself. He refineses it, tests it on more messages, improves his accuracy to 81%. He develops statistical tests to validate his recovered additives. The method works. He knows it works, but nobody will listen to a 17-year-old message sorder. Then on May 11th, 1942, everything changes. Admiral Nimttz arrives at building 1 for an emergency briefing. Japanese radio traffic has exploded.

Something big is coming. Crochor’s team knows it’s a major offensive, but they can’t pinpoint where. The partially broken intercepts mention a location designated AF. Is it Alaska, Australia, the Illusions? They’re flying blind. In the briefing room, tension crackles like static electricity. Roshour presents what little they know. We’re reading maybe 5% of current JN25 traffic. Sir, we can confirm major carrier movements, but locations and timing remain unclear. The additive tables are changed too frequently. We can’t crack them fast enough.

Admiral Nimmits stares at the map. Commander, I need to know where they’re hitting. If I deploy the fleet to the wrong location, we lose the Pacific. Do you understand? Everything depends on you people breaking that code. Sir, we’re doing everything. Andrew Gleason stands up. He doesn’t mean to. His body just moves. Every rule of military protocol says he should sit down and shut up. He’s the lowest ranked person in the room. But the words come out. Sir, I think I know how to break the additives.

The room erupts. Officers shout over each other. Who the hell is this kid? How did a seaman apprentice get into a classified briefing? Rofort looks like he’s aged 10 years in 10 seconds. Gleon, sit down. Angstrom hisses. But I’ve been testing a method. Gleon, sit down. Nimttz holds up a hand. The room falls silent. Let him speak. Andrew’s mouth goes dry. He’s never spoken to an admiral before. He can feel every eye boring into him. His voice cracks as he starts.

Sir, the indicator headers in Tokyo Berlin traffic use split alphabets. A through M one direction, N through Z the other. If we assume plain text follows the same pattern, we can recover additive tables by subtraction. I’ve tested it on 47 messages with 81% accuracy. Lieutenant Commander Thomas Dyer, one of Rofor’s senior cryp analysts, leans forward. That’s Wait, say that again about the alphabet split. Andrew repeats it faster now, more confident. He shows his notebook. The math spills out.

Pattern recognition, frequency analysis, statistical validation. It’s crude compared to the elegant theories the Yale mathematicians use, but it’s concrete. It’s testable. It works. Dyier grabs the notebook, scans it, and his eyes widen. Joe, look at this. The kid might be on to something. Marshall Hall Jr. crowds in. So does Agnes Driscoll. They pass the notebook around, checking calculations, testing assumptions. The room divides instantly. Half the officers think this is absurd, a waste of time from an unqualified child.

The other half sees what Andrew sees, a crack in the fortress wall. This is insane. Captain Joseph Winganger says, “We’re going to bet the Pacific Fleet on the hunches of a teenage file clerk.” “It’s not a hunch,” Dyer counters. “The math is solid. We can test it right now.” On what timeline? Nimmits needs answers in weeks, not months. So, we work faster. Rofort looks at Andrew. Really? Looks at him for the first time. Gleon, how old are you?

Really? The room goes quiet. Andrew feels his forged birth certificate burning a hole in his file somewhere. 19, sir. Uh-huh. And I’m the Queen of England. Roshfort turns to Nimmits. Sir, I don’t care if he’s 12. If this method works, it might give us the breakthrough we need. Nimttz studies Andrew for a long moment, then he nods. Test it. You have 72 hours. If it works, I want every available cryp analyst implementing Gleon’s method immediately. If it doesn’t work, he doesn’t finish the sentence.

He doesn’t need to. CTA one. If you’re fascinated by the untold stories of World War II heroes who changed history, hit that subscribe button. We upload new documentaries every week exploring the people and moments that shaped our world. Don’t miss the next one. 72 hours. Andrew Gleason doesn’t sleep. None of them do. The crypt analysis team divides into two groups. One continuing traditional attacks on JN25, the other testing Andrews indicator subtraction method. The kid who was sorting messages three weeks ago now sits at a table with Agnes Driscoll, Marshall Hall Jr., and Tom Dyer, the best codereers in the American military.

Driscoll handles him roughly at first. She’s broken Japanese, German, and Italian codes. She doesn’t suffer fools, and she especially doesn’t suffer teenage boys who think they’ve discovered something everyone else missed. But as they work through intercept after intercept, her attitude shifts. The method works. More than that, it’s faster than anything they’ve tried. Within 16 hours, they’ve recovered enough additives to begin stripping encryption from current traffic. By hour 36, they’re reading fragments of operational orders. By hour 60, they’ve decoded enough to confirm Rofort’s suspicion.

AF is Midway Island. The Japanese are planning a massive carrier strike in early June. Four to six carriers, dozens of support ships, an invasion force to capture the island. Nimttz gets the intelligence brief on May 14th, 1942. the location, the timing, the force composition, everything he needs to plan an ambush. He sends three carriers, Enterprise, Hornet, and Yorktown, barely repaired from earlier battles, to position themselves northeast of Midway. The Japanese don’t know they’re walking into a trap, but the intelligence keeps coming, and it’s Andrew’s method that’s unlocking it.

By May 27th, OP20G is reading 40% of current JN25 traffic. An unprecedented breakthrough. They identify the Japanese carrier divisions. Akagi, Kaga, Soryu, Heru, the flagship commanders, the attack timeline. Even the morning of June 4th gets confirmation when decoded intercepts reveal Japanese pilots being briefed for dawn strikes on Midways airfield. On June 4th, 1942, at 10:26 a.m., dive bombers from Enterprise and Yorktown catch three Japanese carriers with their decks full of armed and fueled aircraft. In 5 minutes, Akagi, Kaga, and Soru are burning wrecks.

Hiru launches a counter strike that cripples Yorktown, but American bombers find her in the afternoon. By sunset, four Japanese fleet carriers are sinking. Japan loses 248 aircraft, 3,057 men, and its best carrier pilots. The Battle of Midway isn’t just a victory. It’s the turning point of the Pacific War. Before Midway, Japan held the initiative, choosing when and where to strike. After Midway, they’re on the defensive. Their carrier strength shattered, their operational plans exposed. And it happened because a 17-year-old with a forged birth certificate noticed that indicator headers used split alphabets.

After Midway, OP20G becomes an intelligence factory. Andrew’s indicator subtraction method evolves into a comprehensive system for attacking additive tables. The team develops mechanical aids, early IBM tabulators adapted for crypt analysis. By August 1942, they’re reading 60% of JN25 traffic. By October, 75%. The intelligence saves thousands of lives. On August 24th, 1942, decoded JN25 traffic reveals Japanese plans to land reinforcements at Guadal Canal. American naval forces intercept them at the Battle of the Eastern Solomons. The Japanese lose a light carrier and dozens of transport ships.

On October 26th, advanced warning from JN25 decrypts, allows American carriers to ambush a Japanese task force at Santa Cruz. The kill ratios flip. In 1941, Japan sank three American ships for everyone they lost. By late 1942, America is sinking two Japanese ships for everyone lost. Submarine warfare transforms completely. US submarines equipped with decoded Japanese convoy routes begin a campaign of systematic destruction. In 1941, American submarines sank 180,000 tons of Japanese merchant shipping. In 1943, armed with JN25 intelligence, they sink 1.5 million tons.

Japan’s economy strangles. Oil from the Dutch East Indies can’t reach Japanese refineries. Troops in New Guinea and the Philippines run short of food and ammunition. All because American submarines know exactly where the convoys will be. Even the Japanese notice. A captured diary from a Japanese naval officer recovered in late 1943 reads, “The Americans seem to know our movements before we do. How is this possible? Our codes are unbreakable. Our communication officers assure us the enemy cannot read our messages.

Yet their submarines are always waiting. Their carriers always in the right position. It is as if they can read our minds. They could. They were reading the messages. Every operational order, every fleet movement, every convoy route, all decoded, translated, and delivered to American commanders within hours. In November 1943, Fleet Admiral Chester Nimttz visited OP20G. The cryp analysts had just provided intelligence that allowed US forces to ambush and kill Admiral Isuroku Yamamoto, the architect of Pearl Harbor. Nimttz walked through the basement facilities, shook hands with the codereers, and stopped at Andrew Gleason’s desk.

Gleon, now officially 19 and actually 18, stood at attention. At ease, son. Nimtt said, “I’ve read the reports about Midway, about your work on JN25. Do you understand what you accomplished? We broke their code, sir. You did more than that. You saved the Pacific Fleet. You probably saved thousands of American lives. How old are you, really?” Andrew hesitated. The truth seemed absurd now. 18, sir. Nimtt smiled slightly. When this war ends, you’re going to college. That’s an order.

Men like you shouldn’t be filing messages. You should be teaching crypton analysis to the next generation. He paused. But for now, keep breaking their codes. We’re counting on you. The war in the Pacific still had two brutal years to run. But from June 1942 onward, America fought with its eyes open. And every victory, every saved life, every successful ambush traced back in part to a teenager who lied about his age and accidentally cracked an unbreakable code. CTA number two.

This is the kind of history they don’t teach in school. Real people making impossible decisions under incredible pressure. If you’re enjoying this, hit the like button and share it with someone who loves military history. And check out our video on the Battle of Midway to see how this intelligence changed everything. When World War II ended in August 1945, Andrew Gleason faced a choice. The Navy wanted him to stay. The newly formed National Security Agency needed experienced cryp analysts.

They offered him rank, salary, a career in the shadows. But Admiral Nimitz’s order echoed in his mind. You’re going to college. He enrolled at Yale in the fall of 1946 as a freshman. Though he’d already done work that most PhD mathematicians would envy, he never talked about his war service. The codereing remained classified. His classmates had no idea that the quiet guy in their calculus class had helped win the battle of Midway. But the war changed him.

That basement in Pearl Harbor had shown him what mathematics could do when applied to real problems, not abstract theory for its own sake, but concrete puzzles with life or death stakes. He finished his Yale degree in 1949 and joined Harvard’s mathematics department where he would spend the next four decades solving problems everyone else thought were impossible. In 1952, he solved Hilbert’s fifth problem, one of mathematics most famous unsolved challenges. In 1957, he published Gleon’s Theorem, which revolutionized quantum mechanics.

His work on Ramsay theory, coding theory, and mathematical education influenced generations of students. He won the Nukem Cleveland prize, served as president of the American Mathematical Society, and held the Hollis Chair of Mathematics at Harvard. But the codereing stayed classified until 1996 when the NSA began declassifying World War II cryptonalysis records. Researchers finally learned the full story of JN25, OP20G, and the indicator subtraction method that cracked the Japanese naval code. Andrew Gleason’s name appeared in the historical reports, though by then he was in his 70s, more interested in teaching than in rehashing old glories.

In a rare 1990 interview about his war work, Gleon said, “I was young and stupid and lucky. The real heroes were the people like Roshfor and Driscoll who’d been fighting that code for years. I just noticed something they’d been too busy to see. If anything, it proves that sometimes you need fresh eyes on a problem. The experts had been staring at JN25 so long they couldn’t see past their assumptions. The numbers tell the story better than words.

Before Andrew Gleason’s indicator breakthrough in May 1942, OP20G could read 5% of current JN25 traffic. After implementing his method, that jumped to 40% within weeks and 75% by year’s end. Historians estimate the JN25 intelligence directly contributed to sinking over 800 Japanese ships, saving at least 50,000 American lives and shortening the Pacific War by potentially 18 months. Andrew Gleason died on October 17th, 2008 at age 86. His obituaries focused on his mathematical achievements, Hilbert’s fifth problem, his quantum mechanics work, his education reforms.

Most didn’t mention the war. Most didn’t know. But in the Cryptologic Museum at NSA headquarters, there’s a small display about JN25. It mentions Agnes Driscoll, Joe Rashford, Marshall Hall Jr., and other legends of American crypt analysis. And in one corner, there’s a photograph of a baby-faced kid in an ill-fitting Navy uniform standing in front of a desk covered in five-digit number groups. The caption reads, “Saman Andrew M. Gleason, OP20G, 1942. His indicator subtraction method helped break JN25 and win the Battle of Midway.” It doesn’t mention that he was 17.

It doesn’t mention the forged birth certificate, but the historians know, and now so do you. The lesson isn’t about lying to join the military, though thousands of young men did exactly that in World War II. The lesson is about what’s possible when someone refuses to accept that a problem is unsolvable. When fresh eyes look at old assumptions, when a kid who’s not supposed to be in the room speaks up anyway. The code wasn’t really unbreakable. It just needed someone who didn’t know it was supposed to be impossible. And sometimes that’s all it takes to change the world.