Mari Ohki was born in Shizuoka, Japan. She studied organ with Prof. Yuichiro Shiina and harpsichord with Prof. Masaaki Suzuki at the Tokyo National University of Fine Arts and Music, from which she graduated with Distinction as the best student in her year.

During her studies she also took part in organ courses in Germany and won numerous prizes, including among others: First Prize in the audition for the nomination for “Virtuosos in Shizuoka;” Second Prize at the Mainz International Organ Competition; prizewinner at the Possehl Competition in Lübeck; prizewinner of the “Postgraduate AKANTHAS Music Award” in Tokyo. She was also nominated to play in the Gradation Concert for the Japan Organ Society. In September 2012 Ohki won the First Prize at the 3rd International Dietrich Buxtehude Organ Competition on the significant historic organs in Lübeck, as well as the Third Prize and “The Czech Music Fund Foundation Prize” at the 65th International Prague Spring Music Festival in May 2013. In October 2009 she began postgraduate studies with a scholarship from the DAAD with Prof. Arvid Gast at the Musikhochschule in Lübeck, and from April 2012 with Prof. Martin Sander at the Hochschule für Musik in Detmold.
She has appeared as a concert organist in numerous cities in both Japan and Germany, and has taken part in masterclasses with, among others, Harald Vogel, Michael Radulescu, Ludger Lohmann and Lorenzo Ghielmi.