17. Iannis Xenakis’s Hibiki Hana Ma and the Japanese Team for Tekkhokan (Steel Pavilion) at Expo ’70, Osaka

Hibiki-Hana-Ma was one of Xenakis’s electroacoustic pieces which was repeatedly played every day in Tekkhokan during Expo ‘70 in Osaka. In the process of his composition, Xenakis created a music score which was performed and recorded by the Nippon Philharmonic Orchestra conducted by Seiji Ozawa in the Kawaguchi Municipal Hall. Xenakis and Japanese sound engineers worked on editing the tape, according to Xenakis’s notation for multi-layered manipulations, which mainly overlapped various speeds of the recorded sounds. As reported by Sharon Kanach, Xenakis started sketching general sound schema and instrumentation very soon after Toro Takemitsu had commissioned him to compose a new piece. These sketches show several plans of sound movements and the visual images of sounds themselves. In 1969, Yuji Takahashi provided Xenakis information about the architectural features and the sound-control system of Tekkhokan pavillion. The idea of a sound-controlling system, which was very unique and originally designed by Japanese engineers working at that time in Sansei Engineering, had started with Takemitsu’s comments about sound diffusion there: sound movements should not move from point to point, but rather move from ‘phase to phase’, and include global time differences in which the audience should be ‘travelers’ going through the spectrum of different times. The Japanese acousticians calculated twelve directions of 60 degrees as the best shape that would enable the audience to feel that they were surrounded by sound sources from all directions. But Tekkhokan’s diffusion system was not quite suitable enough for Xenakis’s complex ideas. In this chapter, I address this situation based both on meeting minutes of the Japanese team for Tekkhokan composed of musicians, architects, and sound engineers, and on the blueprints made by Sansei Engineering.