Welcome to J-pop week on The 405!

Over the next five days we'll be presenting you with profiles on our favourite J-pop artists, plus a gigantic playlist on Friday. Obviously a week is nowhere near enough time to explore such a comprehensive genre, but we hope it will act as a fairly decent window of discovery. A special shoutout to Bunny Bissoux for all all her help with the artwork, and Patrick St. Michel for his J-pop expertise.

The Sonisphere music festival in Knebworth, at first glance, looks like a perfectly fine event catering to the heavy-metal-leaning crowd. The likes of Metallica, Alice In Chains, Slayer and Dream Theater appear in biggie-sized font, and even Limp Bizkit wriggled their way onto the main stage. Look down just a little though, and one name jumps out - Babymetal, a trio of teenage girls who combine cutesy pop with neck-snapping metal elements. Their video for the peppy 'Give Me Chocolate!' went viral earlier this year (eight-million-plus views and rising) and now they've been invited to play the same stage as Iron Maiden.

Babymetal aren't the only Japanese pop outfit that have gotten looks from outside their home country lately. Colourful pop singer Kyary Pamyu Pamyu turned a bunch of eyeball-grabbing music videos into Internet fame, and rode that success into a world tour featuring a sold-out stop at London's O2 Shepherd's Bush Empire. Holographic star Hatsune Miku secured a spot opening for Lady Gaga on her latest American tour, while on a smaller scale J-pop acts have influenced the likes of Passion Pit, Ryan Hemsworth and Porter Robinson. Yet there's even more intriguing music happening domestically that hasn't gotten many outside looks - although the contemporary J-pop scene relies on only a few marketing strategies, there is an abundance of exciting sonic ideas at the moment worth a look.

When English-language articles bring up "J-pop," it's often as an adjective standing in for hyperactive, squeaky and sugary. This is lazy, the equivalent of lumping Lily Allen, Sam Smith, Duke Dumont and Klaxons together and calling it "B-pop." J-pop in 2014 dabbles in a wide variety of sounds and styles...and sonic variety has been a staple of Japanese pop since its beginning.

Before World War II, the bulk of popular Japanese music merged traditional elements with Western styles such as jazz and blues. Foreign styles continued to be introduced after the war, as American soldiers stationed in the country shared genres like boogie woogie and country with locals. Elvis Presley also made a large impression, and helped to inspire one of the country's stars in the early '60s, Kyu Sakamoto. He holds the distinction of being the only Japanese artist to ever top the United States' music charts, with his 1963 song 'Ue o Muite Aruko' (renamed 'Sukiyaki' internationally). More foreign-born booms followed - The Ventures toured the country and sparked an interest in music made with electric guitar, while The Beatles worldwide popularity and visit to Japan in 1966 helped spark the "group sounds" era of music, highlighted by bands such as The Tigers and The Spiders.

The '70s saw the arrival of "idol music," which has been a cornerstone of J-pop ever since. At the time, idols were any young woman or man considered cute, and they weren't just singers: they appeared in every corner of media possible...but often disappeared quickly. There were exceptions though, such as Momoe Yamaguchi and groups like Candies and Pink Lady. It wasn't just idols though - rock continued to shapeshift, and the trio Yellow Magic Orchestra revolutionized synthpop in the latter part of the decade (and influenced global dance music and hip-hop along the way). The '80s saw a golden-age of idols, along with further commercial inroads for rock, along with a new disco-leaning genre called City Pop which reflected the economic good times Japan experienced during the decade.

The term "J-pop" didn't appear until the '90s, when the Japanese industry got more aggressive about marketing. It was a boom period for sales, and also one where new elements of non-Japanese music seeped in - electronic, hip-hop and especially R&B. The latter was present in the sound of singers like Namie Amuro and Hikaru Utada, who were presented as very different than the idols who came before them. Utada's 1999 album First Love served as the highest peak of J-pop commercially, becoming the best-selling album in Japan and Asia, an achievement it still lays claim to. After that, though, a tighter economy resulted in record sales dropping dramatically, and today the Japanese music industry faces very tough times.

Though they have found some success, even if it's a little sneaky. Idol groups are the current titans of the J-pop charts, highlighted by the massive unit AKB48, an act that boasts a world-record 140 members at the moment - along with various spin-off outfits and sub-groups. They routinely top the year-end sales charts and have become advertising staples, but they've achieved such high numbers thanks to dedicated fans willing to buy multiple copies of their CDs. Part of the appeal of the group is the illusion of personal connection between fans and performers - AKB48 bill themselves as "idols you can meet", and regularly hold handshake events. With one catch - to briefly shake hands with your favorite, you have to buy singles and albums to acquire tickets (or, in a great perversion of democracy, voting ballots for the group's annual election). Dedicated fans buy many copies, juicing sales. Other idols groups - both full of women and men - exploit the same strategy, albeit with less members than AKB.

This has resulted in a proliferation of idol groups, but the need to stand out from the often-peppy masses means some fledgling outfits embrace interesting sonic ideas. The group Momoiro Clover Z zips all over the place, from space-bound rock operas to brostep epics to songs penned by members of The Go! Team. Elsewhere, Dempagumi.inc embrace hyperactive upbeatness, while "anti-idols" have approached pure gabber terror. The concepts can often turn ridiculous - there exists an outfit dedicated to air guitar - but also result in intriguing newcomers like the hip-hop collective Lyrical School or City Pop revivalists Especia. And of course, Babymetal, one of the best examples of a new idol group finding a niche and running with it.

Before the current boom in idol music, there was Perfume. A trio of women hailing from Hiroshima, they were paired up with producer Yasutaka Nakata, who had previously created music for his personal project Capsule. With Perfume, he engineered a breathtaking new sound in J-pop, a maximalist approach where his three singers sounded robotics and every available space filled with an electronic noise. His technopop creations are some of the best pure pop songs of the last decade, and today Perfume remain popular. Nakata now also produces music for the aforementioned Kyary Pamyu Pamyu, conjuring up more playful songs often with a slightly creepy edge to match up with her image.

Other noticeable artists right now include Kaela Kimura, a shapeshifting pop star who started her career as a TV host but now dabbles in sounds ranging from rock to surging electro, and the young-but-quickly-rising Miwa, who plays skippy guitar-pop often accented with synthesizers. Those two owe a debt to Shiina Ringo, an art rocker active since 1998 whose daring approach to pop remains important today. There's an abundance of rock bands who have crossed over to the pop world, but many of them are overly masculine lunkheads who think loud equals good. The biggest exception, however, is Sakanaction, a group originally from Sapporo combining emotional rock music with dance elements, making them stand out from the traditionalist field. Even rap, for a while declining in mainstream visibility, is rallying in interesting ways. See the aggressive electro-poundings of Charisma.com or, for something a bit different, DJ Miso Shiru To MC Gohan, a rapper who studied up on Pete Rock to write rhymes that are actually cooking instructions.

The kitchen directions might be a bit extreme, but right now J-pop is all about fragmentation: the top-selling groups in the country are helped by sneaky sales strategies, while everything else has been reduced to smaller, niche fans. It's tough, then, to really find some of the best artists going right now. The J-pop performers who have made a dent internationally have done so primarily through visuals - Kyary Pamyu Pamyu's videos are must-see events, while Babymetal's heavy metal imagery is every bit as vital to their popularity as the music. Yet there's more to J-pop than that - there's thrilling sounds coming out of Japan too, from all sorts of directions.