One of the oldest chestnuts about inventions involves a 19th-century patent official who resigned because he thought nothing was left to invent. The yarn, which periodically pops up in print, is patently preposterous. “The story was an invention,” says Yoshiro Nakamatsu. “An invention built to last.”

He should know. Nakamatsu—Dr. NakaMats, if you prefer, or, as he prefers, Sir Dr. NakaMats—is an inveterate and inexorable inventor whose biggest claim to fame is the floppy disk. “I became father of the apparatus in 1950,” says Dr. NakaMats, who conceived it at the University of Tokyo while listening to Beethoven’s Symphony No. 5. “There was no mother.”

Though Dr. NakaMats received a Japanese patent in 1952, this virgin birth is disputed by IBM, which insists its own team of engineers developed the device in 1969. Still, to avoid conflicts, Big Blue struck a series of licensing agreements with him in 1979. “My method of digitizing analog technology was the start of Silicon Valley and the information revolution,” Dr. NakaMats says. His voice is low, slow and patronizing, solicitously deliberate. “I am a cross between Steve Jobs and Leonardo da Vinci.”

The floppy is only a short subject in the nonstop invention film that’s running in Dr. NakaMats’ brain. Among his other creations (he will earnestly tell you) are the CD, the DVD, the fax machine, the taxi meter, the digital watch, the karaoke machine, CinemaScope, spring-loaded shoes, fuel-cell-powered boots, an invisible “B-bust bra,” a water-powered engine, the world’s tiniest air conditioner, a self-defense wig that can be swung at an attacker, a pillow that prevents drivers from nodding off behind the wheel, an automated version of the popular Japanese game pachinko, a musical golf putter that pings when the ball is struck properly, a perpetual motion machine that runs on heat and cosmic energy and...much, much more, much of which has never made it out of the multiplex of his mind.

Dr. NakaMats is the progenitor of one other novelty related to floppies: Love Jet, a libido-boosting potion that can be sprayed on the genitalia. The computer component and the mail-order aphrodisiac—and the cash they generate—have taken the inventor of NakaMusic, NakaPaper and NakaVision out of the ranks of the faintly bonkers basement crackpot. The two great financial successes in his perpetual printout of ideas, they give him credibility. Nobody dares to completely kiss off his wilder inventions.

Indeed, Dr. NakaMats has won the grand prize at the International Exposition of Inventors a record 16 times, or so he says, and has been feted all over the world. To commemorate his 1988 visit to the United States, more than roughly a dozen U.S. cities—from San Diego to Pittsburgh—held Dr. NakaMats Days. The State of Maryland made him an honorary citizen, Congress awarded him a Certificate of Special Recognition and then-president George H.W. Bush sent him a congratulatory letter. Dr. NakaMats even tossed out the first pitch at a Pittsburgh Pirates game.

Of all the tributes he says he has received, he is perhaps proudest of having been invested as a knight by the Sovereign Military Hospitaller Order of Saint John of Jerusalem of Rhodes and of Malta, an ancient Roman Catholic charitable order. “Which is why I should be addressed as Sir Dr. NakaMats,” he explains.

He’s saying this from behind a desk in an office of Dr. NakaMats House, a central Tokyo high-rise of his own design. Naturally, the front gate is shaped like a colossal floppy disk.

His office is a riot of not-quite-finished projects. A blackboard is slathered in mathematical equations. File folders are piled on chairs. Copies of books he has written—among them, Invention of Politics and How to Become a Superman Lying Down—are scattered on the floor. Everywhere Dr. NakaMats goes, he dislodges great stacks of scientific papers last examined in, say, 1997. While rummaging for a diagram of his Anti-Gravity Float-Vibrate 3-Dimensional Sonic System, a heap of magazines starts a sort of tsunami across the room, dislodging other heaps in its path. He looks straight ahead, firm and unsmiling.

Dr. NakaMats is lean, moderately intense and 84 years old. He wears a sharp, double-breasted pinstriped suit, a striped red tie with matching pocket square and an expression like Ahab looking for a crew to hunt the white whale. Scrupulously polite, he offers a visitor from the United States a cup of Dr. NakaMats Brain Drink (“Lose weight. Smooth skin. Avoid constipation”) and a plate of intellect-enhancing Dr. NakaMats Yummy Nutri Brain Snacks.

By his count, Dr. NakaMats has clocked 3,377 patents, or three times as many as Thomas Edison (1,093 and no longer counting). “The big difference between Edison and me,” he says, matter-of-factly, “is that he died when he was 84, while I am now just in the middle of my life.”

This conviction is rooted in nutritional research that Dr. NakaMats has been conducting since he was 42, using himself as a guinea pig. “I was curious to see how I could extend my life span,” he says. “And what foods fuel the best inventions.” Which is why he meticulously photographs, catalogs and scrutinizes every meal he eats. He then analyzes samples of his blood and correlates the data. “I have concluded that we eat too much,” he says. “That is what makes life short.”

Dr. NakaMats believes that the right food and drink, moderate exercise and an unflagging love life will keep him alive until 2072. “The number of sleeping hours should be limited to six,” he advises. “Alcohol, tea, milk and tap water are bad for the brain and should be avoided. Coffee is also very dangerous. One meal a day is optimal, and that meal should be low in oil and no more than 700 calories.”

His own diet consists of a single serving of puréed seaweed, cheese, yogurt, eel, eggs, beef, dried shrimp and chicken livers. He seasons this concoction with Dr. NakaMats’ Rebody 55, a dietary supplement comprising 55 grains and several mystery ingredients. “It is ideal for sprinkling on soup or cereal,” he says.

In 2005, Dr. NakaMats’ investigation into the links between eating habits and intelligence earned him an Ig Nobel Prize. Conferred annually at Harvard by the Annals of Improbable Research, a bimonthly journal devoted to scientific humor, the Ig Nobels pay homage to achievements that make people laugh. “Ig Nobel Prize Laureate,” reads Dr. NakaMats’ silver-trimmed business card, which also trumpets his selection “by U.S. Scientific Academy as The Greatest Scientist in The History.”

As it turns out, that academy was the International Tesla Society, a Colorado-based association of inventors. The Tesla Society once issued a card set that showcased influential scientists. Dr. NakaMats made the cut, along with Nikola Tesla, Archimedes, Michael Faraday and Marie Curie. “My card describes me as ‘super inventor,’” he says. “That means I am the greatest.” Somewhere along the line, something was lost in translation.

So what does history’s greatest scientist deem history’s greatest invention? “My answer is, Do you have children?” he tells his American visitor.

Dr. NakaMats has had three. “A child can be invented four ways,” he grumbles. “Smart seed, smart field. Smart seed, stupid field. Stupid seed, smart field. Stupid seed, stupid field.”

And how did his kids turn out?

“All stupid due to stupid field.”

So much for Mrs. NakaMats.

Arguably, Dr. NakaMats’ greatest brainchild is Dr. NakaMats, a scientific superhero for whom exaggeration is a reflex. This is a guy who claims the stabilizer he invented for erratic model airplanes at age 5 “made autopilot possible.”

He has run unsuccessfully for both houses of Parliament and the governorship of Tokyo, racking up nearly 110,000 of the 4.4 million votes in the 2003 governor’s race. “I can make North Korean missiles do a 180-degree U-turn and go right back to their point of origin,” he promised during a 2007 election. “It’s not a secret, exactly. But if I tell you, the enemy might find out.” As Malvolio said in Twelfth Night: “Be not afraid of greatness: some are born great, some achieve greatness, and some have greatness thrust upon them.” Dr. NakaMats believes he’s the sum of those somes.

His genius for self-promotion has not always endeared him to his contemporaries. “Real inventions open our hearts and minds, enrich our lives, bring us closer together,” says countryman Kenji Kawakami, the anarchic founder of chindogu—intentionally silly and impractical creations that are not useful, patented or for sale. “Dr. NakaMats is all about money and fame and ego.”

Kawakami—whose “un-useless” gizmos range from the rotating spaghetti fork to the Grin Grabber, a set of hooks that a grouch slips into his mouth and yanks on to force a smile—may have more in common with Dr. NakaMats than he cares to admit. According to the doctor, many of his contraptions share a single purpose: to increase creativity and human longevity. “Japan’s only natural resources are water, fish, sunlight and brains,” he says. “We must create or die.”

Ever eager to ensure the survival of his country, he invented a musical golf putter called the Secret Weapon. “The club is good for health,” he says. “Because the Secret Weapon can raise a golfer’s accuracy by 93 percent, it lowers his anxiety and blood pressure.” Alas, the Secret Weapon may reduce stress, but it still can’t cure the yips.

Dr. NakaMats is adamant that his “spirit of invention” is neither wealth nor publicity. “My spirit is love,” he says. “Take, for example, my soy sauce pump.” At 14, he watched his mother, a Tokyo schoolteacher named Yoshino, struggle to pour soy sauce from a 20-liter drum into a smaller vessel. “It was a cold winter day during the Second World War,” recalls Dr. NakaMats, whose father, Hajime, was a prosperous banker. “We had no fuel to heat our home.”

Haunted by the image of Yoshino’s trembling hands, he dreamed up a simple appliance, the Shoyu Churu Churu siphon pump. “I loved my mother,” says Dr. NakaMats. “I wished to make her kitchen work easier.” Today the plastic gadget is used to pump kerosene; variations can be found in Japanese hardware stores.

Yoshino, who attended Tokyo Women’s University, began teaching her son physics, chemistry and mathematics when he was a toddler. She encouraged the child prodigy to build prototypes of his inventions and then helped him apply for patents. (He received his first, for a “revolutionary” water heater, in eighth grade). After the war, the bomb shelter in their backyard became the teenager’s workshop. He’d ruminate while listening to a scratchy 78-rpm recording of Beethoven’s Fifth. Eventually, the hissing and popping got so distracting that in 1947, he decided to create a higher-fidelity alternative.

During his studies at the University of Tokyo’s Faculty of Engineering, Dr. NakaMats came up with an analog phonograph record of wood veneer that could be read with magnetic and light sensors. He adapted it for storing memory, replacing the computer industry’s clunky punch cards. That early floppy, he says, is perhaps the purest embodiment of Ikispiration, the Dr. NakaMats system of creativity. Ikispiration has three essential elements: suji (“theory”), pika (“inspiration”) and iki (“practicality”). “To be a successful invention, all three are needed,” says Dr. NakaMats. “Many inventors have pika, but not the iki to realize their dreams.”

In 1953, three years after his floppy breakthrough, he invented a wristwatch with a digital display. It would be another two decades before the Hamilton Watch Company marketed the Pulsar, widely touted as the first digital timepiece.

After five years as a marketer at global trading giant Mitsui, he left to launch the Dr. NakaMats Hi-Tech Innovation Corporation, which, at its height, had more than 100 employees in Tokyo, Osaka and New York. “Most of my staff had been rejected by other Japanese businesses,” he says. “In my country, the most creative people are rejects.” Dr. NakaMats was once a reject, too. He says his floppy disk got brushed off by six major electronics outfits. “Inventions are best developed on your own,” he allows. “When you work for other people or borrow money from them, maintaining freedom of intellect is difficult.”

Dr. NakaMats keeps his intellect free by following a strict daily routine. Every night in his NakaPenthouse, he retires to the Calm Room, which is actually a bathroom tiled in 24-karat gold. “The gold blocks out radio waves and television signals that are harmful to imagination,” he says. The Calm Room was built without nails because “nails reflect thinking.”

After sitting calmly on the toilet for a spell, surrounded by running water, he moves to the Dynamic Room—actually, an elevator—in which Beethoven serenades him.

Dr. NakaMats’ greatest notions tend to surface on long underwater swims. “If you have too much oxygen in your brain, inspiration will not strike,” he cautions. “To starve the brain of oxygen, you must dive deep and allow the water pressure to fill the brain with blood.” He holds his breath as long as he can. “Zero-point-five seconds before death, I visualize an invention,” Dr. NakaMats says. Eureka! He jots the thought on a proprietary waterproof notepad and floats upward.

On a warm evening last spring, Dr. NakaMats once again tempted death by plunging into the private pool at Tokyo’s Okura Hotel. He sank to the bottom and swam back and forth, like a farmer following the plow. A half-minute into his submersion, Dr. NakaMats scribbled frantically on his pad and—literally—came up with a new idea.

Holding the pad aloft, he pointed to a squiggle that, to the untrained eye, resembled a map of the Ginza Line on the Tokyo Metro. “The most terrifying problem facing Japan is how to dispose of radioactive waste from nuclear reactors,” he said. His lips curved into a thin smile. “This is a solution. This is progress.”

His creative juices tapped, Dr. NakaMats returned home, where he unwound in the arms of the Cerebrex Human Performance Enhancing Robot, a hooded lounge chair that cools its user’s head and transmits sound frequencies through his feet. By his calculations, the machine’s pulsating alpha rays improve eyesight by 120 percent, heighten mathematical skills by 129 percent and cram the equivalent of eight hours of quality sleep into one hour of relaxation.

It’s said that 82.7 percent of all statistics are made up on the spot. Which accounts for possibly 93.4 percent of Dr. NakaMats’ scientific calculations. He confides that his Love Jet is “55 times more powerful than Viagra and makes sex 300 percent more fun.” Among the other seemingly magical properties of this liquid lust are memory improvement and skin rejuvenation. “I have tested Love Jet on 10,000 women,” Dr. NakaMats said solemnly as he drifted off to the NakaBedroom. “I do not do the sex. I just check the meters.”