The piano trio is the heart of jazz. This core unit of piano, bass and drums pumps life into the music. All jazz groups, big or small, rely on the piano, bass and drums (called "the rhythm section") for their crucial thrust of energy. Taken out of a larger group, the piano trio contains all the essentials of jazz -- rhythm, harmony and melody -- purely and directly. Without horns or other elements to duck behind, the piano trio puts the resourcefulness and collective feel of the players to the ultimate test. When a different trio's set can be heard one after another, what you get is not just energy but synergy, an apt name for a piano trio festival in Tokyo this month.

Synergy Live 2003, the first event of its kind in Japan, will host seven piano trios from seven different countries for a six-day festival June 17-22. The seven young players invited from Europe, with one from Japan, present a panorama of the most recent innovations and variations of the form. With two different groups playing a full set each day, the event will offer a rare chance to enjoy the "simple complexity" of piano trios. Just as part of the pleasure of World Cup soccer is contrasting team styles at their top level, Synergy Live, while less competitive, will produce illuminating and intriguing contrasts of piano trio styles closely juxtaposed.

The synergy that occurs within trios is particularly intimate, and for this reason, they have long fascinated jazz fans. The interior dialogue of piano, bass and drums is as distinctive as any conversation between close friends. The tight collaborations in the trio unit have led to many key evolutions in jazz. The shift from the classic texture of Miles Davis' first rhythm section (Wynton Kelly, Paul Chambers and Jimmy Cobb) to the daring explorations of Herbie Hancock, Ron Carter and Tony Williams is one of the great divides in jazz. It's easy to focus on the horn men out front and miss the depth of the rhythm section, but every jazz soloist relied deeply on support from piano, bass and drum for their support, energy and ideas.