The song “The Sun is My Enemy,” released 20 years ago on Sept. 1, 1993, may have only reached No. 15 on the Japanese singles charts, but its importance lingers.

This was the first single released by musician Keigo Oyamada under his nom de rock Cornelius, and it’s a key track in the development of the musical movement known as Shibuya-kei, one of the most significant flowerings of creativity Japanese music has ever experienced.

Shibuya-kei didn’t begin with “The Sun is My Enemy.” Oyamada had been running his own Trattoria label — which became one of the foundation stones of the scene — for about a year by this point. Along with singer Kenji Ozawa, he had also formed the band Flipper’s Guitar and made three studio albums between 1989 and 1991, with a post-breakup live release the following year. Shibuya-kei had, in one form or another, been feeling its way into existence for some time.

“The Sun is My Enemy” is, however, a prime example of the sound — or rather the combination of sounds — that came to define Shibuya-kei in the popular imagination. It weds a bossa nova beat to the sort of British 1980s guitar pop best encapsulated by the El Records label (and known to Japanese fans as “neo-acoustic”) and bleeds in threads of jazz, funk and soul. It also brought together the Cornelius name with the Trattoria label and helped set the stage for Japanese music to be cool overseas for the first (and some might argue last) time in its history.

The idea of “Cool Japan” has been around since at least the early part of the century, when Douglas McGray’s influential 2002 essay, “Japan’s Gross National Cool,” was first published. But what neither McGray nor a decade’s worth of drunken, stumbling Ministry of Economy, Trade and Industry (METI) efforts have been able to do is establish what exactly Japan does that is cool.

In the late ’90s, it was Cornelius remixing U.N.K.L.E., Blur and Beck, supporting the Japanese careers of overseas artists such as Apples in Stereo and The Pastels, and promoting Japanese artists such as OOIOO, Asa-Chang, Kahimi Karie and (Oyamada’s future ex-wife) Takako Minekawa. His 1997 album “Fantasma” may not have been what you might call a mainstream hit in Europe and America, but it was definitely cool, becoming an influential touchstone of contemporary indie and electronic music, and an essential part of every music nerd’s record collection.

What Cornelius did with “Fantasma” that so enthralled people was to forcibly expand the musical vocabulary of his listeners, introducing them to sounds they’d never thought of listening to before and colliding genres in ways they’d never known could work. Journalists compared him to Beck with some justification, but his was more a producer’s work than a singer-songwriter’s. It was also even further out there, not obviously rooted in any specific tradition that his listeners could identify, and yet comfortable cutting up and throwing elements of any of them together into the mix.

It was as if just as the public perception of Shibuya-kei began to solidify around the kinds of things he had been doing with songs like “The Sun is My Enemy” (and which Pizzicato Five were also doing to some overseas acclaim), Cornelius was hellbent on exploding each new idea as it came along. He had no time for Shibuya-kei as a genre with its own rules and traditions, and Trattoria’s roster reflected this attitude.

In addition to neo-acoustic bedfellows such as Bridge and Hideki Kaji, and old El Records heroes like the Would-Be-Goods and Louis Philippe, Trattoria also released the grimy garage-punk of Seagull Screaming Kiss Her Kiss Her, the more avant-garde and noise-based sounds of Masaya Nakahara’s Violent Onsen Geisha, and the psychedelic and spacerock-influenced Rovo. The sheer range of material on Trattoria makes it difficult to this day to say with any clarity what Shibuya-kei really sounded like, and yet out of all this, there nevertheless emerged a string of Japanese hits and international collaborations that would be unimaginable in today’s more closed musical environment.

The decline of Shibuya-kei as an important cultural driving force is probably due to a combination of factors. Surely part of it was the need for musicians like Cornelius to stretch themselves and explore new pastures, giving them less time to perform their roles as cultural curators. Indeed, just as McGray was settling in to write his essay on Japan’s cool future in 2002, Trattoria was preparing to call last orders.

In addition, the kind of eclectic Latin-influenced lounge-pop sounds that Oyamada and others such as Pizzicato Five had pioneered were starting to descend into self-parody by the end of the ’90s, while at the same time audience tastes and consumer patterns were starting to shift. A new generation of rock music was emerging from Shibuya’s near neighbor Shimokitazawa, which eschewed the studied air of the Shibuya-kei sophisticates in favor of the more casual styles of Britpop and U.S. alt rock, while the sudden rebirth of idol music as a cultural phenomenon with Morning Musume had helped set mainstream music on the slow, fateful path toward the AKBpocalypse.

Shibuya-kei never died though; it was just always too unstable to remain one thing. It simply diversified, adapted, crossbred with other styles and just generally moved on. There are still people making music that would have seemed quite at home on the Trattoria menu of 1997, while mainstream stars such as Perfume and Kyary Pamyu Pamyu dangle at the end of a long evolutionary chain from Shibuya-kei — in fact the idol scene is peppered with producers whose youthful roots lie in Shibuya-kei. In the indie music sphere, labels like Second Royal in Kyoto and Niw! Records in Tokyo retain some of the eclectic spirit of the ’90s.

Looking at the view from abroad, the impact of Cornelius and Shibuya-kei takes on an extra layer of importance. As “Cool Japan” flag-bearers such as anime collapsed in on itself in a frenzy of Lolita-esque little-sister worship, and even the once-mighty video-game industry started to lose its way, Cornelius is a rare item of Japanese pop culture that retains its cachet overseas. If Japan is serious about using the arts to enhance its cultural clout abroad, it needs to get away from the dogma of “idols, anime and food” and work on fostering a creative base of innovative, independent-minded and inspiring artists who might be able to build on the international goodwill that still lingers from the ’90s.