Primstav (Norwegian Calendar Stick) (挪威木刻曆杖)

The PRIMSTAV — Norway's carved perpetual calendar, in use from about 1300 to 1800 (the oldest dated stave 1457, some 650 preserved): a flat wooden stave turned to its SUMMER SIDE on 14 April and its WINTER SIDE on 14 October, every day a notch and the merkedager cut as symbols — St. Olav's axe at Olsok, the mitten at vinterdag, the cuckoo at gauksmesse, the mill-stone at Hallvardsmesse. On the farm the marks meant WORK and WEATHER: cattle out at Hallvardsmesse, haymaking from knutsok, goats slaughtered at barsok, the autumn's heavy work done by Lussi night. Built the two-witness way: a corroborated CORE of 75 days on which the Norwegian Wikipedia table and Store norske leksikon's complete table agree (count, Olsok's axe and the vinterdag mitten asserted at load); days carried by one table only are served separately with the witness NAMED — real staves varied by region — and the one same-date divergence (22 June) lists both identities, neither blended. Work-rules layered from the University of Oslo almanac survey. DISCLOSED: Norway went Gregorian in 1700 and the merkedag dates carried over nominally — served so, as the tradition settled. Any date returns its side, day-of-side, stave-turn countdown, today's marks, and the next merkedag. The Norse tradition becomes two systems. Pure compute, no LLM.

Cost: 2 TIAN Points per call. tRPC procedure primstav.day.