Hatsune Miku is a singing synthesizer application with a female persona, developed by Crypton Future Media. It uses Yamaha Corporation's Vocaloid 2 synthesizing technology. The name of the character comes from a fusion of the Japanese for first (初 hatsu?), sound (音 ne?) and future (Miku (ミク?) sounds like a nanori reading of future, 未来, normally read as "mirai"), referring to her position as the first of Crypton's "Character Vocal Series". She was the second Vocaloid to be sold using the Vocaloid 2 engine and the first Japanese Vocaloid to use the Japanese version of the Vocaloid 2 engine. Her voice is sampled from Japanese voice actress, Saki Fujita. Hatsune Miku has performed at her concerts onstage as a projection.
Though developed by Yamaha, the marketing of each Vocaloid is left to the respective studios. Yamaha themselves do maintain a degree of promotional efforts in the actual Vocaloid software, as seen when the humanoid robot model HRP-4C was set up to react to three Vocaloids—Hatsune Miku, Megpoid and Crypton's noncommercial Vocaloid software "CV-4Cβ"—as part of promotions for both Yamaha and HRP-4C at CEATEC in 2009. Japanese magazines such as DTM magazine are responsible for the promotion and introduction for many of the Japanese Vocaloids to Japanese Vocaloid fans. It has featured Vocaloids such as Miku, Kagamine Rin and Len, and Megurine Luka, printing some of the sketches by artist Kei and reporting the latest news on the Vocaloids.
Crypton has been involved with the marketing of their Character Vocal Series, particularly Hatsune Miku, which has been actively involved in the GT300 class of the Super GT since 2008 with the support of Good Smile Racing (a branch of Good Smile Company, mainly in charge of car-related products, especially itasha (cars featuring illustrations of anime-styled characters) stickers. Although Good Smile Company was not the first to bring the anime and manga culture to Super GT, it departs from others by featuring itasha directly rather than colorings onto vehicles.
The initial sales of Hatsune Miku were so high that Crypton could not keep up with the demand. In the first 12 days of sale, nearly 3,000 sales reservations were made. This was around one sale in 250 in the music software industry, quoted as "an impossible number" by Wataru Sasaki—the person in charge of the planning and production company 'surprise'. Amazon.co.jp stated on September 12, 2007 that they had sales of Hatsune Miku totaling 57,500,000 yen, making her the number one selling software of that time.
On April 30, 2010, an updated version of Miku called Hatsune Miku Append was released containing a package of six different tones of Miku's voice: Soft (gentle, delicate voice), Sweet (young, chibi voice), Dark (mature, heartbroken-like voice), Vivid (bright, cheerful voice), Solid (loud, clear voice), and Light (innocent, heavenly voice). Miku Append was created to expand Miku's voice library and as such requires the original Miku Hatsune program to be installed on the user's computer first. This was the first time a Vocaloid had such a release, and more Append versions were reported from Crypton Future Media at later dates.
To aid in the production of 3D animations, the program MikuMikuDance was developed as an independent program. The freeware software allowed a boom in fan-made and derivative characters to be developed, as well as acted as a boost for the promoting of the Vocaloid songs themselves. Another Vocaloid tool that was developed was VocaListener, a software package that allows for realistic Vocaloid songs to be produced.
During Miku's development Crypton Future Media decided to take a different approach to that used by the other Vocaloid sound bank publishers. It was decided that to make the product successful not only would a highly appealing voice need to be developed but that voice needed an image. In this way the target focus for Crypton's Vocaloids changed from high end music studios to the general public, specifically teenagers. The task of coming up with Miku's image went to the manga artist Kei Garō. When Kei designed Miku, his only direction was that she was an android and what her color scheme (based on Yamaha's synthesizer's signature cyan color) was. The design on Miku's skirt and boots are based on synthesizer software colors and the bars represent the actual bars within the program's user interface. Miku was originally intended to have a different hairstyle, but Kei stuck to pigtails after trying them out. Crypton then officially created and posted Miku's personal data sheet. However this only contained her 'physical' and technical traits; Crypton did not provide much info in the way of Miku's personality which has allowed song/music video creators and fans to associate the traits that they think suit her best.