Composers are often tempted to exploit the 'exotic' new sounds of non-western instruments such as the Japanese koto, but what are the effects of taking such an instrument away from its traditional context and placing it in a western musical setting? This paper will discuss the extent to which the tuning of the koto contributes to its idiomatic sound and the significance of traditional performance gestures in conveying the distinctive character of the instrument. Traditionally the 13-stringed koto is tuned to a pentatonic scale but its movable bridges lend themselves to experimentation with alternative tunings. Does retuning the instrument compromise its identity? How can non-traditional playing techniques, including the use of electronics, be applied appropriately to a traditional instrument such as the koto? These extensions of the musical capabilities of the instrument are discussed in relation to composition for film music using retuned koto as well as a semi-improvised performance using live electronics.