My article on Horetzky with a facsimile of his Quatre Variations, Op. 22, recently appeared in the GFA Soundboard Volume XXXVII, No. 4. NOTE: I have updated this post with translations from Powrozniak and my comprehensive compositions list. Translations from Bartkowski are forthcoming.
The original title was An Introduction to the History of the Guitar in Japan Including Notes on the First Appearances of the Guitar in Japan and Detailed Biographies of Major Guitarists First Active in the Pre-war Period.