Improvisation is a tricky business. In mediocre hands, it is interminable at best, masturbatory at worst. But with skilled practitioners, improvisation becomes the haute couture of the music world, each piece tailored on the spot to a particular confluence of musicians, audience, time and place.

This is the perfect vibe that organizers of Kobe's Festival Beyond Innocence would like to encourage. By mixing the workhorse of improvisation, the saxophone, with sounds borne of the latest technological innovations in sampling, or crossing the dynamism of a young performer with the resolute experience of an old hand, FBI is all about surprising juxtapositions.

"We try to come up with things that wouldn't happen anywhere else or that would be intriguing or surprising. We don't give a theme to each festival because we do not intend to present things that are already complete or predictable," says festival organizer Kae Uchihashi.

For the last five years, FBI has become Japan's premier venue for progressive music.

"We've had a subtitle for the festival, which translated means 'A provocation toward ignorance; a challenge toward purity,' " says Uchihashi. "It's a desire to provoke the many people who, by saying they don't know this music, refuse to know, or who in not knowing, feel that they know enough."

Kazuhisa, Uchihashi's fellow organizer and husband, is a case in point. As the guitarist for improvisational rock group Altered States, Uchihashi has been a pivotal figure in Japanese progressive music, cited among musical cognoscenti but little known beyond those circles.

His Mutant project, featured at the festival, finds him behind the mixing deck, manipulating the sounds of three saxophones minus reeds. Absent the loud volubility that most people relate with the instrument, it is left dependent on breath and fingering for sound.

As the festival's guiding intelligence, Uchihashi seems to revel in his role as cultural agent provocateur.

The Sound Mail Project, in its third year, is a definitive example. Several musicians are asked to record an improvisation, keeping in mind that it will be played at the festival with another performer. The recording is kept sealed until the day of the festival when Uchihashi chooses another musician for the performance. At that time, the chosen musician is only told the name of the other performer, their instrument and the duration of the recording. The rest is a question of chance and talent. This year's participants span the globe, from Dutch artist Pierre Bastien and his homemade instruments to the Legendary Poptones, a Bulgarian group.

"For the first performer, the collaborator's sound cannot be heard and for the second performer, no matter which way they go or what they do it does not affect the first person's work," says Kae Uchihashi.

"It is a challenge of possibility. To what extent can they coexist and expand the music in a meeting with a time lag? Recording and real-time, the discrepancy of time, restrictions on both sides: It is a project that hopes to highlight these possibilities by confronting these elements head on that are in fact obstacles to improvisation."

Such witty experimentation might strike the neophyte as strange, since the stereotype of improvisation involves sweaty-browed jazz musicians or long-haired rock guitarists. But though the festival is about improvisation, even this implies a unity of outlook that denies the variety of the artists involved.

Special guest vocalist Shelley Hirsch is a veteran of New York's downtown improvisational music scene, but has lately been focusing on her Jewish roots. Han Bennink comes out of a free-jazz background and has played drums with such luminaries as Eric Dolphy.

Bassist Joelle Leandre emerges from yet another tradition. Classically trained and a leading interpreter of John Cage, she is also a noted improviser. A recent piece involved the sounds of domestic household appliances "musically" arranged.

The Japanese roster is equally diverse. Yuji Takahashi is one of Japan's most acclaimed contemporary composers, whose work has recently included both Western and contemporary instruments. Skist is an electronic sound and sampling project of New York percussionist Samm Bennet and sound producer Haruna Ito. Hideaki Sasaki isn't a musician at all but a video artist.

Though their backgrounds may vary, improvisation has become a common conduit of artistic expression.

"Generally speaking, these musicians are active on an individual basis and isolated so there is little interaction between them; practically none when it comes to cross-generational or cross-genre interaction," explains Uchihashi.

"This would create a dead end for the next generation of musicians. We want to present young musicians, together with energetic musicians from around the country, without differentiation or distinction. We hope this can be a place where musicians can challenge themselves and confront their own beliefs."