Sinister Aspect (Left-Hand)

Definition

In traditional aspect doctrine, a sinister aspect is one cast forward — counter-clockwise, in the direction the signs run. A planet aspects sinisterly when it "looks ahead" toward signs that come after it in the zodiac. The Greek term is euōnymos, "left," and the Latin sinister also means "left." A planet in Aries casts a sinister sextile to one in Gemini, a sinister square to one in Cancer, a sinister trine to one in Leo, and so on. Its opposite direction is the dexter, or right, aspect.

In Tradition

In Hellenistic and traditional medieval practice, every aspect except the opposition comes in both a sinister (left) and a dexter (right) form. Holden records the doctrine: "a planet in Aries is in right trine to a planet in Sagittarius, but in left trine to one in Leo. The right aspects were considered to be more favorable than the left aspects." The sinister/dexter split belongs to the older sign-based framework, where an aspect is a directional act of looking rather than a symmetric geometric relationship.

In Practice

Astrologers working in traditional or Hellenistic-revival modes look, for each aspect pair, at which planet "looks ahead" in sign-order — the sinister-casting one — and which "looks back" — the dexter-casting one. This directional difference matters for the doctrine of overcoming, or predomination: a planet casting a sinister square is being overcome by the planet that holds the dexter square, the one ten signs ahead, in the higher tenth-place position. Modern Western practice, working with strictly degree-based symmetric aspects, mostly loses this directional distinction, but it survives in horary, electional, and Hellenistic-revival work.

Historical Origin

The sinister/dexter doctrine is attested across the Hellenistic, Arabic, and Latin medieval literature. Holden records the Greek vocabulary (dexios/euōnymos) and the standard valuation that right aspects are more favorable than left. Crane keeps the doctrine alongside the looking-ahead vocabulary and notes that William Lilly's Christian Astrology (1647) values dexter aspects above sinister ones. The Arabic-Latin medieval tradition retained it too — Bonatti in Tractate VII on aspects, and Al-Biruni's Tafhim cataloguing both terms.

Further Reading