Given the time of the band's formation, it is perhaps understandable that their earlier work provokes frequent comparisons with the then popular and influential "Shibuya-kei" movement, whose most well-known proponents include Cornelius, Pizzicato 5, and Fantastic Plastic Machine.

Capsule's debut album, High Collar Girl, was released in 2001, showcasing many of the bossa nova, French pop, jazz, and naive electronic pop influences that were defining features of the Shibuya-kei genre. Yasutaka formed his own Contemode label for capsule's work as well as other like-minded artist's, under the aegis of Yamaha Music Communications in 2003 and since then, the group has maintained a fairly prolific rate of output, releasing one or two albums a year. 2004's S.F. Sound Furniture saw the group's concept expanding to include the concept of music as a lifestyle accessory, with a retro-futurist visual manifesto displayed in the short film/music video of "Portable Kuko," which was later adapted into a trilogy with the songs "Space Station No.9," from the 2005's SF-themed concept album NEXUS 2060 and "Soratobu Toshikeikaku," which appeared on the same year's L.D.K. Lounge Designers Killer album. Around this time, Yasutaka was also becoming well known as a producer for other acts, and 2006 saw the major-label breakthrough of the Yasutaka-produced idol-pop group Perfume, featuring heavy use of vocoders and dance, house, and electro influences borrowed more from groups like Daft Punk than groups like Pizzicato 5. Many of these sounds had been pioneered by Yasutaka on capsule's work the previous year, and the national success of Perfume catapulted capsule into the public eye.

Subsequent albums pushed the electro influence more and more to the fore, with Fruits Clipper in 2006 and Sugarless Girl in 2007 merging the group's Shibuya-kei lounge pop with guitars and dance beats. 2008's More! More! More! saw capsule's work diverging noticeably with Yasutaka's as a producer, with a much harder electro sound than that displayed on the more mainstream Perfume album, Game, earlier the same year. ~ Ian Martin