In this masterclass, Professor Blacher believes that the piece needs more contrast in general. The student must think in different orchestral colors, e.g. the beginning as trumpets. Moreover, Blacher comments the possibility to change the character using the articulation in a different way (contrast legato-spiccato).
Kolja Blacher explains the meaning of a cadenza: it is the moment where the artists shows their potential and must play as improvising, creating a surprise for the audience (it involves an attitude as a real musician) and breathing and giving more space to the music, more breaks. Tempo must be in relation to the interest of the musical ideas (e.g. going faster in simple passages). They talk about the original cadenza from Beethoven's Violin Concerto.
Finally, Kolja Blacher recommends to the student not to pay attention to the different editions but always considering the general score.
Other topics explained in this masterclass are phrasing, bowings, dynamics and sound levels, style, articulation.