Igbo Market Week (Izu) (伊博四日市集週)

IZU — the living four-day market week of Igboland: Eke, Orie, Afọ, Nkwọ, the four spirits Chineke set over the days, each holding a cardinal direction (east, west, north, south) — and to this day the rhythm by which markets across southeastern Nigeria convene: a town's great market IS its day. TWO INDEPENDENT SERVICES, ONE LINE, asserted at load: MarketDays.ng's live calendar (10 Sep 2026 = Orie, its whole September grid) and AfroTools' anchored calculator (1 Jan 2026 = Orie; 1 Oct = Afọ; 25 Dec = Nkwọ) — six anchors, zero free parameters, all on one continuous JDN line. HONEST SCOPE, per the witnesses themselves: the sequence is shared across Igboland but WHICH markets convene on which day is each town's own (served as caveat, never guessed); the izu ukwu/izu nta great-small pairing varies by community (named, not computed); the Nri month-and-year layer (7 izu = 28-day ọnwa, 13 ọnwa, Ịgụ Arọ) is community-held with no published two-source table — described, refused. Any date returns its market day, direction, position in the izu, and the next eight days. African becomes six systems. Pure compute, no LLM.

Cost: 1 TIAN Points per call. tRPC procedure igbo.day.