Clover White Marking Pen (fine)
The ideal marker for sashiko or marking other dark cotton fabrics, the Clover White Marking Pen is like a rollerball, and produces a fine line, which goes white as it dries - you need to allow a few seconds for the line to show. No need to press hard or scribble the line back and forth, just normal drawing pressure is all you need. The marks don't rub off easily like chalk lines can do and will stay on well even in warm, humid weather. The lines wash out and can also be removed with heat (such as by pressing).