Festival director Chi-hui Yang has a surprise at the 23rd San Francisco Asian American Film Festival, March 10-20. The young but already impressively accomplished Yang is a rock fan, and - besides presenting filmed and live hip-hop, "sleazy rock," indiepop, and post-rock rock as part of the festival - he is also showcasing Margaret Leng Tan. On March 13, in the Castro Theater, the festival's "centerpiece presentation" will be a film about Tan "playing her famous toy pianos." That sounds charming and whimsical, but what a shock is in store for the audience first seeing "Sorceress of the New Piano," and then listening to a live concert by Tan, the subject of the documentary. Yang (and festival programmer Taro Goto) advertise Tan's "experimentations that culminated in her becoming the world's first professional toy pianist (with a nod to Schroeder of `Peanuts' fame)," but that's just a portion of the program. The real thing is Tan's passionate and fearless advocacy and performance of works by some of the most challenging and wildly experimental 20th century composers: Henry Cowell, George Crumb, and John Cage. Not since Michael Tilson Thomas' San Francisco Symphony Maverick series have they received such focussed attention here. Film director Evans Chan traces the history of the Singapore-born New York artist through interviews and performance excerpts, Tan tearing into the bowels of prepared pianos, speaking dismissively of "all those bleeding cuticles," recalling the time when she abandoned music in order to train seeing-eye dogs... until meeting Cage, and joining him to push the boundaries of "classical music." For the festival Website, see http://www.naatanet.org; Tan's Website is at http://home.earthlink.net/~margaretlengtan. Janos Gereben www.sfcv.org [log in to unmask]