Cortex, the Norwegian jazz quartet that has been performing athletic avant-garde jazz since 2007, rely on a well-integrated group sound and a chord-less aesthetic that is both resilient and sparkly. Legal Tender, their fourth release on the Clean Feed Records, comprises seven tracks marked by short and simple themes, productive interplay and exciting improvisation. Six of them were penned by trumpeter Thomas Johansson and one by bassist Ola Høyer. The group also features tenor saxophonist Kristoffer Berre Alberts and the illustrious drummer Gard Nilssen, who makes here his last contribution to this quartet in order to focus more on family as well as on his own projects.

“Anthem For the Uneasy” opens the record with epic grandeur, combining bowed bass legato, dexterous mallet activity and poignant melody. The eloquent, supplicant tones are preserved during the time that Alberts blows a strongly-built tenor improv.

If the groovy avant-garde work in “Standby” emerges with a three time feel, a dash of folk incantation and a fluid swinging vibe, then “GTM” is a playful 4/4 collective exertion with room for the soloists’ creativity. Nilssen stands out in a rhythmic dissertation with occasional beat-driven coolness, opportune fragmentations and lots of color.

Høyer’s “10-4” boasts a two-minute intro of trumpet, peculiarly handled by Johansson with extended techniques. After the sumptuous unisons of the theme statement, the tune segues into a more conversational strategy put in practice by the trumpeter and the saxophonist with occasional wily juxtapositions.

The last couple of pieces on the album introduce the blues as a final fling before the conclusion. Totally relaxed in posture, “Blue Bromka” is pushed forward by sluggish ascendant bass movements and expertly polished brushwork, while “Loose Blues” is divided into two parts, which are separated by more than a minute of silence. Following Nilssen’s introductory mallet drum work and subsequent collective pastoralism, comes a galvanizing and propulsive Afro groove in six over which a fertile trumpet diction unfolds.