On June 19, 1926 Schenker turned 58. A pupil called with greetings:
"Miss Kahn brings roses for my birthday; in taking her leave, she says: 'Only now am I learning to play the piano; I certainly did you wrong in the way I studied, but I cannot learn in any other way'." (diary, OJ 3/8, p. 2949)
The remark may seem glib, even ungrateful when we remember that Marianne Kahn had been a Schenker pupil since 1907 ‒ 19 years! What's more, she was a piano teacher in her own right.
A glance at Schenker's lesson notes enables us to gauge the level at which he taught each student. Take mid-June 1926. First, Gerhard Albersheim: "17th: issues from Mozart's String Quintet in C major, from Mozart's piano sonatas; the Urlinie of the D-major theme from the D-major sonata; about ornaments and their performance"; Robert Brünauer: "15th: concerning neighbor-note motion, accurate graphs, in particular examples from the C#-minor Polonaise"; now Anthony van Hoboken: "14th: things from the secondary literature of the F#-major Nocturne: Galston and Klindworth. Original fingering of Brahms in Op. 116, No. 1; from Mozart's string quartets after the questions Albersheim raised."
Now let's compare two June 1926 lessons for Marianne Kahn: "9th: Beethoven Sonata Op. 81a, first time, all movements; J. S. Bach's first C-minor fugue revisited; 18th: Brahms-Handel Variations revisited."
The difference is immediately apparent. In the first three cases ideas, theoretical issues and techniques, performance and source-studies ‒ these form the subject of the lesson, illustrated by reference to works; one student raises questions. In the case of Kahn, just a string of pieces being played.
There was no one single Schenker method of teaching. He was proud to fashion his instruction to fit the individual ("tailor-made to the person and consolidated as to content," Schenker once called it ‒ OJ 5/5, Aug 12, 1927).Some worked on chamber music or concerto repertory, using him for concert preparation. Others took a systematic course of theory and mastered graphing. Others took editorial studies, working on autographs and first editions. Others were interested in philosophical ideas.
Did Kahn fulfill her promise and change her approach? She remained a pupil of Schenker's at least until 1932. Here are the two last-recorded lessons, from May 1932: "4th: [Chopin Etudes] Op. 10, No. 6 E-flat-minor, Op. 10, No. 7 C major, Op. 10, No. 8"; "18th: repeated, lovely! Nocturne, Op. 27, No. 2 D-flat major." — She was not alone: Schenker usually had two or three students who simply worked on repertory, without taking counterpoint, harmony, figured bass or other studies, as the "heavyweight" students did. Such students no doubt provided him with a stable and constant income ‒ in Kahn's case for 25-plus years.