Place the needle (or stick) vertically on the drawing, on the spot corresponding to the current time (hour)
Rotate BUSO until the needle’s shadow overlaps the intersection spot between the mark corresponding to the current month of the year and the vertical axis of BUSO
This is the North-South axis. You can now place the map accordingly. Even better, you can stick the BUSO drawing onto your map, with the N mark aligned with the north on the map.
How to make a solar compass
You need a watch, a needle (or a tiny stick) and this drawing, named BUSO by its inventor:
This is an example of BUSO in use:
