Rising Dutch reeds improviser Tineke Postma is the second young female alto-sax original to hit London in seven days, preceded by Chicago's Matana Roberts on a flying visit last week. While Roberts is a gospel-hot yet turbulent improviser, Postma is cooler and more ruminative. Her work is audibly affected by the abstract lyricism of Wayne Shorter, though her American teachers David Liebman and Chris Potter also seem to have had a hand in her uptempo authority and rhythmic impetus.

But Postma is making a mark with her own sound - and, like Roberts, she is bending the resources of the alto saxophone toward new tonal subtleties, while reinforcing a tenor-like low-end punch. She began by skimming through a couple of fast originals, then confirmed her improvisational class with a Sonny Rollins-like inclination to move from one guiding motif to another to create episodes and drama in the solo. However, at all speeds, she preserves a warm and distinctive tonal glow.

Inevitably, she adopted the soprano saxophone for the Shorter tribute Short Confessions, quoting from that sax genius's great themes, but applying her own blends of purring extended sounds, soft multi-phonics, and a trademark contentment to leave some phrases unresolved. On the Michel Legrand ballad What Are You Doing the Rest of Your Life?, Postma hinted at both Lee Konitz and Jan Garbarek in her savouring of long tones, or notes disappearing into puffs of air. She is an intriguing new arrival.

· At Pizza Express Jazz Club, London, tonight. Box office: 020-7439 8722.