Mazas Violin Duos A practical guide for violinists The 14 duo collections published mostly in sets of 6 (in two volumes (cahiers, Hefte) of three works each) by Litolff, Peters and others (1850-1900) with Heim's grading system Heim 1-4: 1^st position, 5-7: 1^st to 3^rd position, 8-10 all positions easy, 11-15 all positions difiicult, 16-20 all positions very difficult
1^st Position H2 Op.85, Vols.1 and 2 H3 Op.85, Vol.3 H4 Op.38, Vol.1 Op.46, Nos.1 and 2	1^st to 3^rd Positions H5 Op.60 H7 Op.38, Vol.2 (except Nos.10 and 11) Op.39, Nos.2 and 3 Op.61 (except No.5) Op.62, Nos.2 and3 Op.70, Vol.1 Op.71, Vol.1 Op.82, Vol.1	1^st to 5^th Positions H8 Op.38, Vol.2 Nos.10 and 11 Op.39, Vol.1 No.1; Vol.2 Op.46, Nos.3, 4, 5, 6 Op.61, No.5 Op.62, No.1 Op.70, Vol.2 Op.71, Vol.2 Op.72, Vol.1 Op.82, Vol.2 Op.86, Vol.1 Nos.2 and 3; Vol.2 No.4; Vol.3 Nos.7 and 8 H9 Op.40, Vol.1 Op.72, Vol.2 Op.86, Vol.1 No.1; Vol.2 Nos.5 and 6; Vol.3 No.9 H10 Op.40, Vol.2	1^st to 7^th Positions H12 Op.41