Born in Tokyo 1984, Mari Adachi began the violin at the age of four. She studied violin and viola at the Toho Gakuen Music School and she has been pursuing her career in viola since 2004.
She continued her studies of viola performance with Siegfried Führlinger and chamber music with Johannes Meissl at the Vienna University of Music and Performing Arts. In 2013 she graduated with the highest mark and distinction on her Master Diploma and in 2015 she graduated for her Soloist Master Diploma at The Lausanne Conservatory.
Since 2012 she has been a member of Camerata de Lausanne directed by Pierre Amoyal and she performs in Switzerland, France, Turkey, Russia. Since 2013 she was the associate principal violist at the Tirol Symphony Orchestra in Innsbruck in Austria. In 2014 she played in Bemberg Symphony as a guest principal violist. Since 2015 she is based in Japan as a soloist and a member of Quartetto L'estro Armonico.
In 2015, She played Martinu's Rhapsody Concerto with Lausanne Chamber Orchestra. The same year in the summer, she played in Montreux Jazz Festival. She is active also in a wide range of genres.
In 2014 at the Verbier International Music Festival in Switzerland she coached the chamber music lessons for amateur. She has begun to teach.
She participated in the "Saito Kinen Chamber Music Study Group for young people". She trained in NHK Symphony Orchestra as an academy students from 2007 to 2009.
In 2009 She played the principal viola in Seiji Ozawa Music School Opera projects and Orchestra projects in Japan and China.
She got the special Award and the excellent performance Award at the Kirishima International Music Festival in 2005,1st prize and the Ravel Award at 6th Osaka International Music Competition ensemble department. At the International Academy in Semmering in Austria, she won the soloist prize in 2010, 2011 and 2013. In 2011 at the Baden-Baden Carl Flesch Academy, she played Bartok's viola concerto with Baden-Baden Philharmonic Symphony Orchestra and won the special award.
She studies the violin under Isako Shinozaki, the viola under Mazumi Tanamura, Siegfried Führlinger, Nobuko Imai, Gilad Karni, chamber music under Johannes Meissl. And she attended a number of master classes in Japan and Europe.