(LKM Music). These delightful etudes by Ernesto Koehler (Op. 33) have endless benefits for an intermediate player. Each one succinctly addresses a particular idea be it articulation, phrasing, or an expressive gesture consistently throughout the etude. Thus their instruction is focused and, due to their brevity, a student can be assigned two to four a week. Consequently, the rewards are great! Book 2 includes 12 Medium Difficult Exercises .