Folk inauspicious days mapped onto solar dates, 2026 to 2035

Conventions taken

THESE FOUR ARE FOLK CONVENTIONS, NOT MEASUREMENTS. They cannot be derived from astronomy the way solar terms or new moons can; they are tables copied in almanacs, and the almanacs differ in places. The Sat Chu and Tho Tu tables here were cross-checked against Vietnamese feng shui sources in current circulation, all of which cite Ngoc Hap Thong Thu without quoting it, so this is the convention IN CIRCULATION rather than a reading of the source text. Tho Tu has two methods and the table gives both: the tho_tu column judges stem and branch together, so one day per lunar month, while tho_tu_theo_chi judges the branch alone and marks many more. Sat Chu splits into Yin and Yang as two different tables, which many places merge without saying which. Leap months use the table of the main month; some schools use the preceding month instead, and the ghi_chu column flags those days.