Music examinations frequently require students to harmonise chorale melodies ‘in the style of J. S. Bach’, but the manner in which the skill is taught generally emphasises the adding of chords below the melody note by note ‘arithmetically’, and may thus fail to develop inner hearing and a sense of overall harmonic direction. Using the system of ‘harmonic sketching’ which she developed originally as an approach to keyboard harmony and described in detail in her book Sketching at the Keyboard, Laura Campbell extended the technique to the harmonisation of chorale melodies, in the process comparing her students' choices of outline harmony with those employed by Bach in four settings of the same chorale. In this article she describes the experiment and comments upon its results, showing how the ‘sketching’ method, which reveals the fundamental ‘harmonic landscape’ of a melody, is an especially valuable tool in the acquisition of written harmony skills.