Brass Jaw, Pizza Express Jazz Club, London

Sober-suited Brass Jaw are a quartet of Scottish saxophonists willing to take the risk of performing unaccompanied. There is no drummer’s thump to hide the occasional glitch, and no piano or guitar to remind soloists where they are in the scheme of things. Yet without resort to barnstorming histrionics or instrument-swapping theatrics, they delivered full-blooded, on-the-edge arrangements that, for two sets, riveted this somewhat sparse jazz-club audience.

Their opening number had so many twists and turns that it fully lived up to its title “The Nasty”. A brief unaccompanied alto sax melody was tossed around the ensemble and then distended into a controlled anarchic rumble. Enter a bluesy riff, lush harmonies punctuated by sudden stabs and slurs, and then an angular, wickedly fast alto saxophone melody emerged from the melange. They seemed to have done it all in the first number, but this wide-ranging virtuosity was maintained throughout the gig. Lilting township rhythms yielded to abstract washes, funky grooves came to an abrupt stop and quick-fire ensemble passages were densely harmonised, and played with the confidence that comes from continuous collaboration – they are midway through a UK tour, and also core members of the Scottish National Jazz Orchestra’s brass section.

With baritone sax taking on the arduous duty of replacing the bass – Allon Beauvoisin has a nice line in funky riffs and walking bass, and the stamina to keep going without a break – the two altos and tenor were free to roam round the saxophone’s lush sonorities. And properly anchored they could project their solo strength – tenor saxophonist Konrad Wiszniewski all tumbling cadenzas and breathy balladry, Paul Towndrow and Martin Kershaw equally fleet-fingered but neatly contrasting rhythmic awareness and harmonic intellect on altos.

But chamber jazz stands or falls by its writing. Theirs is top notch. Strong structures and a grasp of tradition give the ensembles an identifiably and richly harmonised sound, tea-shop sweet on Gershwin’s “Our Love is Here to Stay”, spiritually moving on their transcription of a guitarist’s rendition of Coltrane’s “Afro Blue”. And with sudden silences, ululating altos and swoops and slurs sprinkled around, there were loads of details to keep you focused.