Tenchūsatsu (天中殺 Void Periods) (天中殺)

TENCHŪSATSU (天中殺) — Japan's void-period system, the sanmeigaku doctrine that from every birth day pillar follow two void branches, and with them TWO VOID YEARS in every twelve, two void months in every year, two void days in every twelve — the famous periods when 'heaven does not answer' and tradition counsels rest over launches. Japanese magazines print the six groups (子丑・寅卯・辰巳・午未・申酉・戌亥) the way the West prints Sun signs. THE PARTITION IS A THEOREM, PROVEN AT LOAD: the sixty pillars split into six decades of ten; each decade uses ten of the twelve branches and its void pair is EXACTLY the two left over — derived by formula, proven for every decade, spot-pinned to the canonical 甲子旬 → 戌亥 — plus a FULL-CYCLE CROSS-ENGINE LAW: the formula must agree with the independent lunar-javascript engine's own 旬空 across 120 consecutive real days, all sixty pillars twice, zero divergence. Serves the group with readings, current in/out-of-void status, the next two-year window, the 節切り void months (lineage difference on boundaries disclosed), and upcoming void days with their pillars shown. THE RAILS: the tradition's counsel is reported as the TRADITION'S teaching, never advice; the commercial derivative Rokusei Senjutsu (大殺界) is NAMED as a descendant, not served. Japanese becomes eighteen systems. Pure compute, no LLM.

Cost: 1 TIAN Points per call. tRPC procedure tenchusatsu.period.