Art may largely be a matter of taste, but one conclusion is close to inarguable: 1998 was the best year ever for video games, producing an unparalleled lineup of revolutionary releases that left indelible legacies and spawned series and subcultures that persist today. Throughout the year, The Ringer’s gaming enthusiasts will be paying tribute to the legendary titles turning 20 in 2018 by replaying them for the umpteenth time or playing them for the first time, talking to the people who made them, and analyzing both what made them great and how they made later games greater.

They came tumbling out of the Kansas sky, 10 yellow bulbs growing larger with each passing moment. By the time the skydivers touched down at Topeka’s Forbes Field, a crowd of children had gathered to gawk. Other airborne goods followed: 750 plush yellow mice were fixed to miniature parachutes and sent drifting into the bright, late-summer sky, airdropped from the belly of a plane as though by a foreign power with superior resources—which, strictly speaking, was more or less what was happening.

The children no longer resided in Topeka at all. The mayor had declared that, at least for one day, August 27, 1998, the city would be renamed in honor of its rodent invader: Topikachu. The skydivers ditched their human-sized parachutes and made for the fleet of 10 identical, just-released Volkswagen New Beetles, each painted yellow, with two pointy ears fixed to the roof and a telltale lightning bolt tail on the back, and the words “Gotta catch ’em all!” painted delicately on the doors. From there, the Beetles set off to spread the gospel of Pokémon to 10 other U.S. cities.

Within weeks, thousands of American children would pick up Game Boys, slot in red or blue cartridges, and hear for the first time the opening jingle alongside a splash of credits for the young Nintendo collaborator Game Freak: Bah-dah-dah dah-daah-dah-dah-daaah, Bah-dah-dah dah-dah dah-daaah.

As those notes first played, they—and their parents—couldn’t have grasped the extent to which this world of electric mice, stubborn caterpillars, and drowsy gorillas would come to dominate their own. They couldn’t have guessed at all the things still to come, at least on this side of the Pacific: the TV show and movies and toys, the schools so desperate to reclaim their students’ attention that they banned the binders of trading cards that would shortly become ubiquitous. Nor could anyone that day in Kansas possibly have anticipated the game’s longevity, that the creatures would still have so much resonance two decades later that a mobile phone game featuring them would be a worldwide sensation and an upcoming live-action film about—what else?—the antics of Pikachu would be stuffed with Hollywood A-listers.

In this, the families picking up Pokémon Red or Blue for the first time in 1998 were hardly alone: Even the man who wrote that opening song, along with all the others on Red and Blue, never imagined any of this when he was perched over a Game Boy coding village theme songs and battle cries in Tokyo. “Not at all!” Junichi Masuda says now. “Even today, I’m still surprised.”

Now, of course, much to do with Pokémon is different. Since the launch of the first Game Boy games, Game Freak has released 28 different titles, with the 29th and 30th—the companion pair Let’s Go, Pikachu! and Let’s Go, Eevee!—due out this November on the Nintendo Switch. These are joined by a host of other games developed beyond Game Freak’s walls, from 1999’s Pokémon Snap and Pokémon Stadium for Nintendo 64 to 2016’s blockbuster Pokémon Go, created by mobile developer Niantic.

The number of collectible creatures has ballooned from the original 151 in Red and Blue: The modern collector now seeks out 807 different cartoon beasts, from the Zapdos and Gyarados of old to the more modern Xurkitree (a humanoid tangle of electric cords) and Vanilluxe (an enormous, two-headed ice cream cone). The live-action film Detective Pikachu, based on the 2016 Nintendo 3DS game of the same name, is slated to debut next May, with the titular Pikachu voiced by Ryan Reynolds. The world of Pokémon is vast.

But the more things change in the Pokéverse, the more they remain the same. Twenty-two years after the first Pokémon game debuted in Japan, and 20 years after the elaborate stateside launch in Topeka-as-Topikachu, Red and Blue composer Masuda, 50, is still thinking about the battle cries of different Pokémon. But he isn’t just composing anymore: He now leads Game Freak as the company’s director, having served variously as producer, director, and composer for the many Pokémon video games that have followed the original series, as well as the company’s other, non-Pokémon titles. Together with Game Freak’s creative brain trust, Masuda is the architect of the better part of the last two decades of international Pokémania.

These days, Masuda’s work isn’t just about the music. But it was always about the music first—for him as well as the Pokémon franchise. From those giddy introductory notes on, Masuda was building a world that would make a permanent home in our collective imagination. Pokémon is nothing if not an earworm.

Game Freak began as a ragtag group of developers under Satoshi Tajiri in 1989. Masuda met Tajiri when he was just 19 and a computer graphics student at a technical college in Tokyo. Tajiri later asked Masuda to score one of the fledgling company’s earliest games, the arcade puzzle Mendel Palace for NES.

Tajiri’s childhood memories of catching bugs inspired the game that eventually became Pokémon’s first edition, Pokémon Red and Green. Game Freak was a tiny studio with a handful of modest early successes under its belt, including Yoshi, a popular puzzle game based on the Mario character, that stood as the company’s first title for Nintendo. But Nintendo passed on Tajiri’s first Pokémon pitch, so the project idled in the background for six years.

Unlike with most video game composing, both then and now, Masuda wasn’t given finished visuals to score for Red and Green. Development of the game was ongoing, so the young composer made do with guessing what sequences might look like.

There was an early emphasis on music at Nintendo, where composer Koji Kondo penned the instant-classic scores of 1985’s Super Mario Bros. and 1986’s The Legend of Zelda. The limitations for composers on early Nintendo platforms were twofold. The systems had narrow selections of audio “channels”—essentially, how many different sounds can play at once: The NES, released in 1983, had five sound channels, while the SNES, released in 1990, had a comparatively generous eight. The Game Boy had just four. The second hurdle was size: The sound files themselves needed to be miniscule—even the SNES could manage only 64 kilobytes of audio RAM. These restrictions forced composers to recycle portions of their tunes over and over again to save space, resulting in spare, looping soundtracks that reinforced central themes. The most successful composers were often those who found the most creative workarounds—people like David Wise, whose inventive use of overlapping samples in the score of 1994’s Donkey Kong Country was recently highlighted by The Nerdwriter.

Composing for the Game Boy was an arduous process, Masuda explained to me this summer, through a translator. The Game Boy’s four-channel sound system consisted of two pulse waves, a wave channel, and a noise channel. With the noise channel typically in use for Pokémon’s sounds effects, Masuda had to create the actual music—the melody and bass—using just the remaining three channels, something roughly akin to trying to type an emoji with a calculator.

“As a result, I set the rhythm using bass sounds,” he says. “Not only that, but since memory was so limited, I ended up repeating a lot of musical intervals over and over again to save space.”

The goal, he says, was to use the music to build something distinct that felt like the real world—but was entirely its own. “Take the Kanto region from the original Pokémon Red and Pokémon Blue games,” he says of the first generation of 151 Pokémon. “It was inspired by the region in Japan of the same name and we used that to design the layout of the game world, but I went out of my way to avoid using traditional Japanese music for the game in order to make it feel like a completely new world.”

It’s difficult now to overstate just how great a sensation Pokémon caused upon its 1998 U.S. debut. In Japan, the games—released, as in the U.S., as a near-identical pair, Red and Green—had found a wildly passionate audience after their initial release in early 1996. From there, they moved organically to other platforms. The hugely popular anime, for one, didn’t arrive until a year after the games, and the Game Freak team regarded it at first with wariness: “We weren’t really sure about it,” Masuda told Game Informer last year.

There was no uncertainty when it came time to break into the North American market two years later. Nintendo coordinated the Pokérollout for maximum effect—which is to say wall-to-wall saturation. Corporate licensing agreements were hammered out before the first American Pidgey was ever evolved. The trading card company Topps signed a deal with Nintendo to turn the creatures into a card game; Hasbro coined the “Gotta catch ’em all!” slogan to push its line of dolls and plushies. And that’s not the only Pokémon hallmark that was thought up outside Game Freak: The tendency of Pokémon to repeat their own names—“Pika pika!”—came from a Japanese film production studio, as did the idea to promote Pikachu, which the studio had noticed was particularly popular with schoolkids, as an especially important character.

As the American invasion began, it helped that much of the work had already been done in Japan. The anime was simply translated into English and given some minor alterations for North American audiences: The central trainer, originally named Satoshi after Game Freak’s founder, was renamed Ash Ketchum; rice balls, a common Japanese snack, were described as “jelly doughnuts” or else superimposed over with images of sandwiches.

And so when the match was finally struck in Kansas, prospective consumers were practically helpless to resist. Editorials began to fill newspapers addressing bewildered parents: What was Pokémon, and why had our sons and daughters suddenly become obsessed? The fanaticism grew in the months after the game’s launch: The search engine Lycos debuted a rolling list of its top 50 most frequently searched queries in 1999; Pokémon took the no. 1 spot and remained there for the next year. The so-called “Pokéflu” swept schools’ absentee lists with the release of Pokémon: The First Movie on a Wednesday in November 1999. Burger King was forced to apologize when a Pokémon card promotion timed to run with the movie’s release ran out of its card supply early. “We could not have anticipated the kind of demand we have experienced in the last two weeks,” the company’s North American president wrote in an apology that ran in The New York Times, USA Today, the Los Angeles Times, and The Dallas Morning News. Topps predicted in an earnings call that its annual revenue would soar 40 percent in 1999 on the basis of Pokémon products alone.

Counterfeiters swooped in to try to capture some of the craze: During the last six months of 1999, U.S. Customs officials seized more than $20 million worth of counterfeit Pokémon merchandise. At a pair of toy wholesalers in Los Angeles that July, 540,000 counterfeit cards were seized. Nintendo issued an advisory for how to spot fakes (thinner cards might have “crinkles”).

Not everyone was a fan of the animated onslaught. A Colorado Springs pastor proclaimed to his church that Pokémon was an occult symbol and then incinerated a pile of the collectible cards with a blowtorch while his 9-year-old son decapitated a Pokémon doll by his side. Time ran a cover story with the words “Beware of the Pokemania.” “Is Pokémon payback for our get-rich-quick era,” the authors asked, “with our offspring led away like lemmings by Pied Poké-Pipers of greed?”

None of this did much to dampen the obsession. By the end of 1999, Pokémon products had grossed $7 billion worldwide.

For children of the ’90s, the musical score of Pokémon Red and Pokémon Blue (Green was outdated by the time the North American launch rolled around) is intensely evocative. Take a whirl through “Pallet Town” or the battle theme and the nostalgia pours in. For me, “Pokémon Center” brings back vivid memories of trading creatures with my little brother, our Game Boys tethered together on our living room carpet. The theme of Lavender Town, an area dominated by Ghost-type Pokémon, has been remixed by many a DJ and been the subject of dark creepypasta stories about the mystical properties of its coded score. The score as a whole has been covered at length, and some of its pieces have been incorporated into other Nintendo titles, like Super Smash Bros.

The music has also been the subject of at least one academic dissertation, by then–Brown student Mark Benis, who in 2011 began the painstaking process of transcribing the entire Red/Blue score note by note. Six years later, he published a 173-page dissection of it, complete with music theory analysis of each piece. (“Relief is perhaps the strongest emotion that the player feels after capturing a Pokémon, especially if it is rare or even legendary,” Benis wrote of the ditty that plays whenever a Pokémon is caught. “Masuda’s short fanfare conveys that emotion as well as a hint of excitement with repeated statements of the following rhythm.”)

Benis didn’t set out to transcribe the whole of Masuda’s score. A violinist, he’d gone to college to study engineering. But early in his freshman year, he began to wonder if he might be able to do composition instead. Lacking the formal background of many of his musical classmates, Benis decided to transcribe the Pokémon Center theme to learn the basics of composition. “I think part of it was that I just didn’t understand how the music worked,” he says. “I loved it, I listened to it as a kid when I played the game, but I just didn’t understand it.”

Breaking down Game Boy music required reverse-engineering the confines that Masuda and other composers of that era worked in. First, Benis found music files for Red and Blue, which he broke apart into their four foundational channels, each of which he then wrote out one by one. The process of reconstructing the themes proved addictive. “I thought, well, if I did a few, why don’t I just do a few more?” he says.

Benis, now in a master’s program for film and video game scoring at NYU, compares Masuda’s Red/Blue Pokémon score to the work of Johann Sebastian Bach. The baroque composer is considered the patron saint of the musical technique called counterpoint—the playing of multiple pieces of independent music simultaneously that together create something greater than the sum of their parts.

“He wrote a lot of piano music,” says Benis, “and the idea was that even though you have two hands, you can play three lines of music, and each one can sound musically brilliant just playing it alone. But when you put it together, it creates this harmony, and you can hear the harmony at any one given time, or you can listen to each line individually and trace them, and hear them as they move.”

That concept, Benis says, reverberates throughout Pokémon music. “If you’re going to limit yourself to the same limitations that Game Boy music had, you have to write three lines of music that all sound brilliant on their own, and put them together,” he says. “It’s almost like a puzzle. I think of Junichi Masuda as a really good puzzle maker.”

In 2014, The Pokémon Company—the Tokyo-based entity eventually incorporated to keep track of the myriad licensing ventures leading out of Game Freak, Nintendo, and the developer Creatures, which has collaborated on non–Game Freak Pokémon games like Pokémon Stadium and Detective Pikachu—launched a global orchestral tour, with symphonies playing live renditions of Pokémon music as the corresponding game sequences played out on a screen above them.

Jake Kaufman, a video game composer whose low-fi soundtrack to 2014 cult favorite Shovel Knight has been compared to Masuda’s early Pokémon work, arranged a pair of Masuda songs for the Pokémon: Symphonic Evolutions tour. Kaufman concedes that in spite of the influence of chiptune, as 8-bit music is known now, on his work, he’d never been much of a Pokémon fan. But as he immersed himself in the games and their music while preparing for Symphonic Evolutions, something changed.

“I was hooked,” Kaufman says. “Masuda-San”—many people in the video game industry, whether or not they work with the Game Freak director, refer to the composer as either “Masuda-San” or “Mr. Masuda”—“helped me evolve essentially against my wishes, but I’m so happy in my new form. To me, that is a clear sign that he’s truly the Master he wants us all to be, and a genius who will live forever.”

Pokémon was the fastest-selling title in the Game Boy’s 10-year history. It was a watershed moment for the company, and one that has continued to reverberate into the present. Two decades after the first outbreak of Pokémania, some 300 million Pokémon video games have sold worldwide. Pokémon is the highest-grossing media franchise in the world, surpassing Mickey Mouse, Harry Potter, myriad comic book heroes, and even the greater Star Wars universe, which had a 19-year head start. The augmented reality–infused Pokémon Go, which sucked in a dizzying 300 million players in the weeks after its July 2016 release, was written off by many as a short-lived “mass-consumption nostalgia product” for millennials—but two years on, the game still has 60 million active players and, as of July, had raked in nearly $2 billion.

Pokémon Go wasn’t the first time detractors wrote off Pokémon as a passing craze. After 1999’s Pokémon Gold and Silver, Game Freak’s sequel to the Red/Blue/Green franchise, Satoshi Tajiri moved to a supervisory executive producer role. Masuda, whose background spanned music and graphics alike, stepped in to direct what would become the series’ third edition, 2002’s Ruby and Sapphire. He has described the latter as the most challenging of the Pokémon games he’s worked on. “After Gold and Silver came out, it was a huge hit around the world,” Masuda told Game Informer, “but shortly after everyone was saying, ‘That’s it. The Pokémon fad is over! It’s dead!’”

The morning after the release of Ruby and Sapphire, Masuda went to a local store, where he was relieved to see a line of people waiting to buy the new games. “We at Game Freak took that as a challenge and said, ‘It’s not dead. We’re going to show you guys you’re wrong!’”

The Pokémon score as it exists today is something of a mashup of original pieces from Red/Blue/Green, and newer tunes, some of which lean into genres like jazz and EDM. A form of the original Pokémon Center theme, for example, remains in the game’s latest edition.

“I tend to focus on the target audience of each game when coming up with the music and sometimes that does mean appealing to player nostalgia,” Masuda says. “In the upcoming Pokémon: Let’s Go, Pikachu! and Pokémon: Let’s Go, Eevee! I envisioned that players would be enjoying the games in their living rooms beside their friends and family, so I used more orchestral-sounding music in order to make less intimidating than, say, rock music or techno music, which can be quite polarizing.”

He composes today as he did at the start: alone, preferring to work out a melody in his head before committing it to pen and paper (or, more often, screen). “I don’t experiment on a piano until I come up with” a melody, he says. And he still tries to build musical worlds that feel like someplace real—but not so much that they make players doubt that they’re somewhere totally new.

“The region in Pokémon Sun and Pokémon Moon”—a duo released in 2016 for the Nintendo 3DS—“was inspired by Hawaii,” Masuda says. “I tried to incorporate some rhythms reminiscent of Hawaii while using a tonal structure that makes the setting feel fresh.”

For Masuda, even his most iconic creations feel malleable from game to game. “Personally, I don’t feel like there is anything that cannot be changed,” Masuda says of the Pokémon score.

He struggles to choose a favorite song from all these years of Pokémon music. “I really like the Pokémon Center theme, the wild Pokémon battle music, the Trainer battle music, the Viridian Forest theme and the Pewter City theme, and of course the music that plays during the final battle,” he says. “But I think my favorite might be the title-screen song that the player first hears after they turn on the game. I feel like it is the most representative of that ‘Pokémon feel.’”

“Wouldn’t you agree,” Masuda asks, “that it makes you feel as if your adventure with Pokémon has just begun?”