The Kodály Method Vol. 5

"77 Two-Part Exercises" came into being to supply the need for exercises shorter and easier than others in the series "66 Two-Part Exercises" to "22 Two-Part Exercises". It is important to practise two-part singing from the very beginning ; at first with hand-signs, then by sol-fa letters, and, as soon as the pupils are reading music, from staff notation. [... ] Besides archaic Hungarian songs I have tried to use and adapt into two-part settings some very interesting Ainou motives taken from the collection of Mr Kazuyuki Tanimoto and Mr Yuki Masuda, issued by the Tokyo Radio.
Sight-reading must at all times offer fresh material, including some unusual turns of melody and rhythm, but remaining always sound and attractive music, never degeneration into mere mechanical exercises. Two-part sight-reading without any instrument is the most effective means of making rapid progress and acquiring confidence in both rhythm and intonation. Movable "Doh" helps the understanding of modulation and the musical significance of each note of a melody.
Without this no thorough musicianship is possible". Zontán Kodály Instrumentation : children's choir