the mandala is not only a means of expression but also produces an effect. It reacts upon its maker. Age-old magical effects lie hidden in this symbol, for it is derived from the 'protective circle' or 'charmed circle,' whose magic has been preserved in countless folk customs.!7 It has the obvious purpose of drawing a sulcus primigenius, a magical furrow around the centre, the temple or temenos (sacred precinct), of the innermost personality, in order to prevent an 'outflowing' or to guard by apotropaic means against distracting influences from outside. Magical practices are nothing but projections of psychic events, which then exert a counter-influence on the psyche and put a kind of spell upon the personality.
— Joan Chodorow
Jung's claim here is not that the mandala is a pretty picture of wholeness — it is a defense work. The sulcus primigenius, the first furrow, was the line a Roman founder plowed around the city's edge before anything was built, and what could not be carried across it could not enter. To draw a mandala is to perform that founding gesture inward: to mark where the self ends and the dissolving force begins.
This matters because the temptation with centering practices is to read them as arrival — the circle completed, the center found, integration achieved. Jung refuses that reading here. The circle is not a resting place; it is a perimeter. It exists because something threatens to outflow, something else threatens to intrude. The magic is real precisely as psychology: the act of drawing the boundary changes the psychic economy of the person drawing it, not by summoning peace but by instantiating a structure that the psyche can orient around.
What the mandala protects is not the self in some stable, achieved sense. It protects the capacity for a center to hold at all — which is an entirely different claim, and a more honest one. The circle says: here, for now, is where I am. Not: I have arrived.
Joan Chodorow·Jung on Active Imagination·1997