This school taught math, physics, and chemistry, but the whole world ran on life-point calculations?

At seven forty in the morning, the doorbell was being pressed like an ambulance alarm.

Yūki had just woken from a light sleep.

In his dream, he had been leaning behind a three-meter-thick concrete riot shield when a burly man with a 3,000 ATK boss monster charged headfirst into it, suffered an immediate concussion, and was carried away on a stretcher.

He shuffled over in flip-flops and opened the door.

A KC Logistics courier stood outside and handed him two express packages covered in security seals.

"Mr. Fujiwara Yūki? Your same-city express delivery. Please sign here."

After signing, Yūki carried the heavy packages inside. The snip of scissors cutting through tape was crisp and pleasing.

He laid the newly unpacked cards out on the table one by one.

Two [Stealth Bird], two [Wave-Motion Cannon], two [Level Limit - Area B], two [Pot of Greed], and those two [Magic Cylinder] that positively radiated an air of psychological torment.

Add in the [Giant Soldier of Stone], [Holy Barrier], and generic traps the body's original owner had left behind.

Exactly forty cards.

Not one more, not one less.

To a modern competitive card player, keeping the main deck at the forty-card minimum was an instinct etched into their DNA.

If anyone dared stuff in one extra random card, it felt as revolting as sucking a fly up through a bubble tea straw.

Yūki slid the neatly squared main deck into the main compartment of his black deck box.

Then he opened the concealed compartment at the bottom and securely locked a dozen or so forbidden goods, including [Confiscation], [Delinquent Duo], [Yata-Garasu], and [Don Zaloog], into the side-deck slot, all specially chosen to shred his opponents' nerves.

The main deck would turtle up and burn life points; the side deck would harvest souls.

He needed both approaches, and both had to be strong.

Yūki snapped the deck box shut and tucked it into the innermost pocket of his schoolbag.

The instant his fingers touched the shell of the deck box, his fingertips grew slightly warm.

That itch after fine-tuning a diabolical build, that impatience to find some innocent passerby and test its power-even in another world, it felt exactly the same.

Domino City Third Middle School.

Second-period math that morning.

The teacher at the front held a piece of chalk and rapidly drew parabolas on the blackboard, its tip striking the board with short, monotonous taps.

Outside the window, a lower-grade PE class was practicing basic movements on the sports field.

Students from two classes stood in neat square formations, thrust their arms forward, and unfolded their Duel Disks in perfect unison, shouting their slogan so loudly that dust rose across the field.

"In my name, I summon!"

Yūki occupied the heavenly seat in the second-to-last row by the window, his textbook open at the corner of his desk as his pen traced bored circles on scratch paper.

In his previous life, anyone practicing like that on the sports field would probably have been dragged off by their homeroom teacher for a psychiatric appointment within half an hour.

But in this world, this was an extremely serious form of physical and mental training.

Because in this world, Duel Monsters projections were formed from compressed physical particles, and the willpower of top duelists could even induce physical resonance.

One blast from Blue-Eyes White Dragon could overturn a truck, and one wave of Dark Magician's staff could black out the entire city.

Whoever played cards best stood at the top of the food chain.

Even the Chazz Princeton Foundation, which threw its weight around the business world, with one older brother wielding power in politics and the other calling the shots in business, had an ultimate family trump card: pouring all its resources into the youngest brother, Chazz Princeton, in hopes that he would dominate the professional dueling world.

"Politics and business serving as logistics for card players... this magical realism really is pretty convincing."

Yūki wrote a simple number on his scratch paper: [4000].

In this world of universal obsession, everyone treated playing cards as a hot-blooded sport.

But as a thoroughly seasoned veteran, Yūki saw nothing but an extremely simple arithmetic problem.

4,000 life points.

If he played like these innocent youngsters, summoning a low-level monster with 1,800 ATK to crash into an opposing monster with 1,400 ATK, he would only knock off a measly 400 life points per turn.

He would have to swing for ten whole turns!

Along the way, he might even run into some unknown trap, or get kicked to death when his opponent suddenly whipped out a boss monster.

But what if he switched to stall burn?

One sit-up from Stealth Bird: 1,000 points.

Each turn Wave-Motion Cannon charged in the back row: 1,000 points.

With [Level Limit - Area B] underfoot and [Magic Cylinder] set in the back row, even if his opponent stacked a monster's ATK all the way to ten thousand, it could only stand rooted like a wooden dummy in front of his defenses.

"Extremely high mathematical expectation, maximum consistency, and absolutely no risk of running into a trap when declaring an attack."

Yūki twirled his pen, his lips curving into an innocent smile.

"Now this is the exam-focused strategy that best fits well-rounded education."

Still, if he wanted to take next month's Duel Academy entrance exam, there was one hard requirement he had yet to meet.

Eligibility to register for the practical exam required [Two-Star Duelist] status.

The body's original owner was still stuck at the very bottom rank: [One-Star].

In the Kaiba Corporation's official certification system, one star roughly meant "knows monsters can attack people and can tell red traps from green traps."

The only way to advance to two stars was to defeat an opponent of the same rank or higher in an official duel recorded by an official terminal.

Only two days remained before registration closed.

Yūki felt the heavy deck box inside his schoolbag.

His deck was ready.

The only thing he needed now was an innocent test subject who wasn't too bright but had a high enough star rating.

"Clang! Clang! Clang!"

The shrill end-of-class bell erupted through the hallway, right on schedule.