Revised Julian Calendar (Orthodox New Calendar) (修正儒略曆)

THE REVISED JULIAN CALENDAR — Milanković's 1923 reform from the Congress of Constantinople, the calendar that SPLIT the Orthodox world's fixed feasts: New-Calendar communions keep Christmas on 25 December, Old-Calendar communions on the unrevised Julian reckoning — 7 January today, and 8 JANUARY from 2101, a drift this engine PROVES from the two calendars' own arithmetic rather than reciting. One leap rule is the whole system: century years are leap only when they leave remainder 200 or 600 on division by 900 — mean year 365+218/900 days, CLOSER to the tropical year than the Gregorian's — and the engine's epoch is DERIVED from the congress's own synchronization (1 October 1923 Julian = 14 October 1923), never hand-copied. LAWS AT LOAD: the Gregorian-identity window pinned at BOTH ends — it opens 1 March 1600 (Gregorian 1600 is leap, Revised Julian is not) and closes 28 February 2800, with every century year checked between — the 2800 divergence and 2900 realignment asserted, 218 leaps per 900-year cycle counted, and the Old-Calendar Christmas anchors (7 January through 2100, 8 January from 2101) falling out of the arithmetic. Serves any civil date on all THREE reckonings (Gregorian, Revised Julian, Julian) with the menaion's great feasts checked on both styles, the communion lists as living fact (the 2023 OCU/UGCC adoptions recorded), and the 1923 compromise disclosed: PASCHA stays on the Julian computus for nearly all — the Finnish exception named. Christian becomes three systems. Pure compute, no LLM.

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