After Mr. Kubo graduated from Tokyo University of Fine Arts and Music in 1968, he pursued studies with Hiroshi Tamura, Yoichiro Miyake, and Max Egger. He continued to improve his skills in West Germany and other areas in 1972, 1975, and 1980-81. He has been especially active in the field of duo piano, and has performed duo concerts every year since 1973 with Rainer Hoffmann (Professor, Frankfurt Music Academy), receiving high accolades for their splendid performances. They have more than 100 pieces in their repertoire such as a piano duet recording covering Beethoven and Schumann pieces, and a compact disc featuring their 18th Live Duo Concert.

Mr Kubo's activities include numerous joint performances with Johannes Walter (solo flutist of Dresden Staats Kapelle) from 1973 to 1989, an FM radio broadcast with an NHK Symphony member, and The Tailich Quartet in 1990 (Brahms Piano Quintet). He made a speech on the "Educational Value of Duet Playing" at the conference of the European Piano Teachers Association in London in 1988, and served as a lecturer for an extension course held at the British Piano Duo Association in London in 1995 and at the "International Musik-Projecte Bremen" in 1998. He has edited the duo Hungarian dance and waltze pieces by Brahms and has written extensively about piano duo for music magazines. He was invited to serve on the jury of the Reding-Piette International Two Piano Competition in Switzerland in 2001.

Mr. Kubo is chairman of the Japan Piano Teachers Association international department and a director of the International Piano Duo Association in Japan. He has held classes for duo piano since 1973 at Ferris Women's College and is now a professor of undergraduate and graduate courses at Ferris University. Professor Kubo is Chair of the Instrumental Division in the College of Music.