Ok, first a little lesson of 2 commonly misused terms, spine & spline. Very simple, a "spline" is a thin flexible strip of wood, metal, etc. A strip of bamboo used to make a bamboo rod is a "spline". A spine is a backbone. A graphite rod has a spine, not a spline. So by definition the spine(backbone) is the side opposite to the guides. I made the same mistake before being corrected by a top bamboo rodmaker.