Her high-tech invention is called the Laser Koto, a tripod-mounted laser array which replaces the strings of a traditional koto with lasers. Masaoka 'plays' the instrument by moving her hands through the beams, her movements triggering sampled and processed sounds from her Apple G4 PowerBook. Each movement of her fingers and hands is interpreted as a stroke on the instrument's virtual strings, according to Wired.com.
The Laser Koto is equipped with four separate laser beams that Masaoka calls "metaphorical strings." These are a set of light sensors that register when the beams are broken by the movements of her hands and arms; there are also, writes Wired.com, infrared proximity sensors that establish her distance to the posts on which the lasers are mounted.
The instrument grew out of an earlier project Masaoka completed in the late 1990s called the Koto Monster, which was a koto fitted with motion sensors and effect pedals attached to a MIDI interface. Masaoka initially installed laser arrays above and below the instrument's body, then decided to get rid of everything but the lasers.
Masaoka has been developing koto interfaces with MIDI controllers since the 1980s. She builds interfaces with the computer and koto, at times using pedals, light sensors, motion sensors and ultrasound. With the koto connected directly to her laptop, she records her playing live, and processes the samples in real time. An active composer, she has also written scores for ensembles, chamber orchestras and mixed choirs. In her performance pieces she has investigated the sound and movement of insects, as well as the physiological responses of plants, the human brain, and her own body.