Mirror is the first ECM New Series album devoted to the Estonian composer Tõnu Kõrvits (born 1969), a portrait in six works for cello, voices and strings. Kõrvits ties his writing closely to his country's song tradition, and the presence of Veljo Tormis, whose songs underlie three of the pieces, is felt across the programme. Like the older composer, he draws on folk song and archaic melody, heard here through a refined, densely layered sound of strings and choir with the cello as recurring protagonist.

The soloist is the cellist Anja Lechner, whose meeting with the composer was the starting point of the project. She is joined by the singer Kadri Voorand, the Tallinn Chamber Orchestra and the Estonian Philharmonic Chamber Choir, all conducted by Tõnu Kaljuste. Kõrvits himself plays the kannel, the Estonian psaltery. The recording was made in February 2013 at the Methodist Church in Tallinn and mixed there in December 2014. Manfred Eicher produced it, Tanel Klesment was the recording engineer, and Paul Griffiths wrote the liner notes.

The largest work is Seitsme linnu seitse und (Seven Dreams of Seven Birds, 2009, revised 2012), on words by the poet Maarja Kangro and the composer. It is both a choral suite and a cello concerto, with the choir singing in Estonian and English while the cello conjures birdsong and swooping flight. The opening Peegeldused tasasest maast (2013), for cello and choir, is a fantasy on a song by Tormis and Paul-Eerik Rummo, and it fades into an open, plucked instrumental coda. Around these two pieces stand the seven-part string suite Labürindid (2010) and two Tormis arrangements from 2008. Tasase maa laul puts Voorand's voice and the kannel in front of the strings. Viimane laev, on a text by Juhan Smuul, is set for male choir, bass drum and strings. The short Laul for cello and strings closes the disc.

Raymond Tuttle wrote in Fanfare that he hoped the album would do for Kõrvits "what early ECM New Series releases did for fellow Estonian composer Arvo Pärt". He described music that dwells in a meditative space, where small gestures count for much, and praised the atmosphere of the church recording. Dominy Clements, in MusicWeb International in 2016, singled out the particular quality of the Estonian choral sound and gave the CD his "unreserved recommendation".

CD edition of ECM New Series 2327, first released on 18 March 2016, with a booklet containing Paul Griffiths' notes.