Accélération is the only ECM album by the Swiss trio of reed player Hans Koch, bassist and cellist Martin Schütz and drummer Marco Käppeli. Released in 1988, it is a set of nine short, sharply drawn pieces, all written by Koch, that range from a shy csárdás and a waltz to dense, driving group playing. It also marks the start of the long partnership between Koch and Schütz that later led to the trio Koch-Schütz-Studer.

Koch and Schütz, both based in Biel, met at the conservatory in 1978 and formed the trio with Käppeli at the start of the 1980s. They began by playing jazz standards before turning to their own material. Koch plays clarinet, bass clarinet, tenor and soprano saxophones, and Schütz switches between bass and cello, which gives the group two very different lower voices. The album was recorded digitally in June 1987 at Tonstudio Bauer in Ludwigsburg, with Martin Wieland as engineer and Manfred Eicher as producer.

The pieces are compact, most under seven minutes, and Midori is the longest at almost nine, with Schütz working against busy, insistent drumming. Shy Csárdás opens with trembling cello and pointillist strokes on the cymbal rims before Koch's clarinet takes the lead. Im Delirium sets his tenor saxophone, heard here for the only time, over a waltzing bass. Glas(s)no(s)t is built on a close exchange between cello and soprano saxophone, and the album ends with the brief, playful GG-U-GG-U-RR-U-GG.

The record has stayed one of the less-known titles of ECM's 1980s catalogue, though it has its advocates. Revisiting it on ECM Reviews in 2012, Tyran Grillo called Midori "a synaesthetic exercise" and named the album "a personal favorite among ECM's lesser-knowns". The trio recorded a second album for Sound Aspects in 1988. From 1990 Koch and Schütz worked with drummer Fredy Studer, adding samplers and electric cello on a series of records for Intakt, beginning with Hardcore Chambermusic in 1995.

This is the CD edition of ECM 1357 (also numbered 833 473-2), first released in March 1988, with cover photograph and design by Dieter Rehm.