Short version of the double capo technique for Praise Him Moon and Stars by Graham Kendrick.
Long version here: https://www.youtube.com/watch?v=ILpj_wtBf8c
Full song here: https://www.youtube.com/watch?v=YXG_m-2fGTI
Song Story: https://www.youtube.com/watch?v=yIwT5T_iUtQ