Circle Fretting System (C.F.S.) Slightly curved frets are mounted as each string and fret intersect at right angles to minimize the contact surface. You can obtain accurate pitch, cleaner longer sustain and true harmonics. *The frets we use aren't special. You can ask your nearest repair shop to hit them from the edge of the fingerboard when refret. J-Standard Fret Edge FUJIGEN craftsman's handmade fret edge contributes to much smoother fingering.