Horā (Lanna holasat / horasat) is the reckoning of time and fortune: the lunar-solar calendar (patithin), the choice of auspicious and inauspicious days (wan di wan sia), the casting of a birth-chart (duang chata), and the long planetary periods that a diviner reads over a life. It descends from Indian jyotiṣa, carried north through Mon and Burmese intermediaries and then reworked in Tai hands, so a Lanna horā manuscript sits at the meeting point of Sanskritic astronomy and local almanac practice.
For this archive this is a research-priority genre. Horā is living knowledge — a mo duu still consults these tables today — which makes the manuscripts easy to contextualise against active practice and a natural bridge between the historical record and the contemporary vernacular.
Horā in this catalogue is an upper-northern tradition. It clusters in Phayao and Lampang ahead of Chiang Mai, Nan and Chiang Rai — the old muang of the Ping, Wang and upper Yom basins — with the largest single holdings at Wat Chiang Man, Wat Phra That Lampang Luang and Wat Si Khom Kham. Almost every witness is written in Tham Lanna script in the mixed Pali-and-Lan Na register typical of the region's learned texts.
The most telling pattern is physical. Where the canonical genres are overwhelmingly palm-leaf, horā leans the other way — toward mulberry-paper folding books (phap sa). That is not an accident of survival: an almanac is a working reference, opened flat and read across a spread, and the concertina phap sa is the tool for the job in a way a bound stack of palm-leaves is not. When you browse this genre and see paper outrunning leaf, you are seeing the genre's use fossilised in its support.
Many titles here read Holasat plainly, but a good number pair it with Sainyasat (saiyasat, protective magic) or katha in a single volume — "Katha tang tang, Sainyasat", "Holasat, Tholanisan". In practice the diviner and the ritualist were often the same person, and a household manual bound the calendar next to the protective verse. The catalogue's genre line records the dominant content, but the real object is frequently a hybrid. The companion article on Magic & Ritual is the other half of this world.