Kav קו

Kav (קו, “line, measuring-cord”) is the Lurianic name for the single straight ray of Ein Sof’s light that is drawn, after the contraction (tzimtzum), from the surrounding light through one point into the vacated space (chalal). In Chayyim Vital’s Etz Chaim (Sha’ar 1) it is the kav yashar (the straight line) and a tzinor daq (a thin channel): the conduit along which all emanation descends, and the principle that, with the concentric igulim (circles), constitutes the two modes of every world.

The kav resolves the problem the tzimtzum creates. Once Ein Sof has withdrawn to leave a round void, divinity must re-enter that void in a measured way, or creation would either not occur at all or would be reabsorbed into the boundless light. The kav is that measured re-entry: a thin line, deliberately not broad, so that the emanated receive light in measure (bi-middah) rather than in the boundless manner of the Emanator. It is the single thread that joins the finite worlds to their infinite source.

Etymology

Kav (qof-vav) is a common Hebrew noun for a line, a measuring-cord, a plumb-line (Isaiah 28:17, “I will make justice the line”; 2 Kings 21:13). The measuring sense is doctrinally apt: the kav is not only a line but a measure, the instrument by which the emanated come to have middah and gevul (measure and limit). Vital exploits exactly this resonance when he explains that the sefirot are called eser middot (“ten measures”) because the thin line conveys only a measured, bounded illumination.

Place in the cosmogony

In Derush Igulim ve-Yosher (Sha’ar 1, ch. 2) the kav has three load-bearing properties. First, its asymmetry: its upper head is drawn from Ein Sof and touches it, while its lower end does not reach the light that surrounds beneath — and this asymmetry is what constitutes orientation itself, “above and below, head and foot.” Were the light supplied from both ends, or from every side equally, there would be no above or below at all. Second, its thinness: the line is daq me’od (very thin), so that the emanated receive “sufficient for their need … and not too much.” Third, its double work: as the kav spreads it loops into the ten concentric igulim (circles) and also runs straight down as the yosher (the upright figure of supernal Adam) — one line generating both configurations. The kav is thus the connective tissue of the whole created order: “the aspect that joins all the circles together is this thin line.”

Usage across traditions

Tradition	Figure	Text	Specific sense	Citation
Jewish mysticism	Chayyim Vital	Etz Chaim, Sha’ar 1	The kav yashar / tzinor daq drawn from Ein Sof into the chalal; its head touches the Infinite, its foot does not, constituting orientation; the channel of measured light	Derush Igulim ve-Yosher, ch. 2
Jewish mysticism T	Zohar (cited by Vital)	Tikkunei Zohar / Idra	The line / measure imagery and the contrast between Ein Sof, which has no measure or known name, and the sefirot, each of which has a known name and measure	cited at Etz Chaim, Sha’ar 1, ch. 2

Cross-tradition parallels marked T reflect documented historical transmission with the transmission channel named above. Parallels marked S reflect structural analogy: independent developments that converge on similar conceptual territory. The distinction is editorial not evaluative.

Jewish mysticism Chayyim Vital

Etz Chaim, Sha’ar 1

The kav yashar / tzinor daq drawn from Ein Sof into the chalal; its head touches the Infinite, its foot does not, constituting orientation; the channel of measured light

Derush Igulim ve-Yosher, ch. 2

Jewish mysticism T Zohar (cited by Vital)

Tikkunei Zohar / Idra

The line / measure imagery and the contrast between Ein Sof, which has no measure or known name, and the sefirot, each of which has a known name and measure

cited at Etz Chaim, Sha’ar 1, ch. 2

Notes

The kav is frequently paired in later Kabbalah and Hasidism with the reshimu (residue): the line of fresh light descends into a void that already retains the trace of the withdrawn light, and the interaction of kav and reshimu becomes a standard frame for discussing how bounded existence is sustained. In the developed Lurianic system the kav is also the spine of Adam Kadmon: the lights that later emerge through Adam Kadmon’s “apertures” (ears, nose, mouth, eyes) are elaborations of the single line first drawn into the chalal.

A rendering note: kav is “the line” or “the ray,” and its concrete geometric sense should be preserved; it is not “the column” (which is the yosher figure) nor a generic “emanation.” The Lurianic geometry is figurative of a process in the divine life, but the image is doctrinally load-bearing and is not to be dissolved into abstraction.

Primary sources

• Etz Chaim, Sha’ar 1, Derush Igulim ve-Yosher, ch. 2 (Vital, recording Luria) — the drawing of the kav and the origin of orientation.

Scholarly literature

• Scholem, Major Trends in Jewish Mysticism, Seventh Lecture — the kav within the Lurianic account of emanation after the withdrawal.
• Fine, Physician of the Soul, Healer of the Cosmos — the Lurianic cosmogony in its Safed context.
• Menzi and Padeh, The Tree of Life (1999) — the standard modern English of the early gates of Etz Chaim.

Hekhal Editorial. "Kav." Hekhal: An Open Reference for Esoteric Tradition. Last modified May 2, 2026. https://hekhal.org/lexicon/kav.

Hekhal Editorial. 2026. "Kav." Hekhal: An Open Reference for Esoteric Tradition. https://hekhal.org/lexicon/kav.

Hekhal Editorial. "Kav." Hekhal: An Open Reference for Esoteric Tradition, May 2, 2026, hekhal.org/lexicon/kav.

Hekhal Editorial. (2026). Kav. Hekhal: An Open Reference for Esoteric Tradition. https://hekhal.org/lexicon/kav

@misc{hekhal-lexicon-kav-2026,
  author       = {{Hekhal Editorial}},
  title        = {{Kav}},
  year         = {2026},
  publisher    = {{Hekhal: An Open Reference for Esoteric Tradition}},
  url          = {https://hekhal.org/lexicon/kav},
  urldate      = {[date accessed]}
}