Folk Taboo Days (楊公忌・三娘煞・月忌)

The three great fixed-rule taboo strata of the Chinese folk almanac, each with its structural law machine-asserted: 楊公忌日 — Yang Yunsong's thirteen days (1/13, 2/11 … 12/19), every date exactly two days earlier than the last with month seven alone doubled (the receding-two law); 三娘煞 — the Third Maiden's six wedding-taboo days (初三·初七·十三·十八·廿二·廿七), spited weddings from the matchmaker legend; 月忌日 — 初五·十四·廿三, the days the 五黃 sits in the rotating Luoshu's centre (each ≡ 5 mod 9), the days of the proverb 「初五、十四、二十三，太上老君不出庵」. Check any civil date (converted through the real lunar calendar, with the next 30 days' hits) or a lunar date directly; leap-month convention stated. The folk layers beside the almanac's computed 建除/十二神/28-mansion strata — calendar culture for reflection, not advice.

Cost: 1 TIAN Points per call. tRPC procedure folkTaboos.check.