/worldbuilding

Calendars, Seasons, and Moons

A secondary world with its own calendar needs one written record, or dates drift: a festival lands in two different months, a full moon rises twice in a week, the harvest comes before the thaw.

Record the calendar as a system file

story add system "Reckoning of Vell" --type social

Fill worldbuilding/systems/reckoning-of-vell.md with:

## Overview

Twelve months of 30 days plus five festival days at midwinter (365 days).
Years are counted from the Founding (AF).

## Rules & Limitations

| # | Month | Days | Season | Notes |
|---|-------|------|--------|-------|
| 1 | Thaw | 30 | spring | Year begins at the first thaw |
| 2 | Sowing | 30 | spring | |
| ... | | | | |
| 12 | Frost | 30 | winter | |
| - | Hollow Days | 5 | winter | Festival; not part of any month |

- Week: 6 days (Firstday ... Restday). Markets on Firstday.
- Day: dawn bell, noon bell, dusk bell; hours not counted by commoners.
- Moons: Ser (29-day cycle), Oda (41-day cycle). Both full on 1 Thaw 412 AF.
- Leap rule: none.

## Conversion

Scene `date` field = ISO bookkeeping date. 1 Thaw 412 AF = 2001-03-01.

Keep holidays, market days, tides, and anything the plot hangs on in the same file.

Dating scenes

The CLI's date fields accept only YYYY-MM-DD, and story continuity, story timeline, and the route check compute elapsed time from them. For an invented calendar, map in-world days onto ISO dates with a fixed offset:

1. Pick an anchor: the first in-world day of the story equals an ISO date (1 Thaw 412 AF = 2001-03-01). Record it under ## Conversion.
2. Count days, not months. If in-world months differ from Gregorian ones, convert through the day number: story day 45 is the anchor plus 44 days.
3. Put the ISO date in the scene or chapter date field and the in-world date in the prose or the scene body. Use time for the time of day.
4. Keep a small conversion table under ## Conversion for dates the story uses often (festivals, deadlines, full moons).

The ISO date is a bookkeeping device; readers never see it. What matters is that elapsed days are right, so the travel check and timeline ordering work.

Seasons and daylight

Record for each season: day length, weather, what grows, what travel is possible (passes closed, rivers frozen or in flood), and what work people are doing. Route hours assume normal conditions; note seasonal exceptions in the location body.

Moons and cycles

For each moon or cycle, record its period in days and one date when it was full (or at any fixed phase). The phase on day N is (N - known full day) mod period. Check any scene that mentions moonlight, tides, or a moon-bound ritual against this. Two moons align every least common multiple of their periods (29 and 41 days: every 1,189 days), which makes a good rare event.

Checking

• story timeline . lists dated scenes in story-time order and flags scenes read after events that happen later.
• story diagram timeline prints a Mermaid timeline of dated scenes and chapters.
• story continuity . checks clock order, travel-hours, and routes. It reads scene date, time, location, characters, and pov; chapter dates do not feed the route check. A named time is a span (morning is 05:00-11:59), an untimed scene spans its whole day, and only journeys impossible on every reading are errors. travel-hours on a scene is the minimum time since the latest moment the story has reached in reading order (a flashback does not reset it), not a journey within the scene.

After adding or changing the calendar system, run story reindex ., story links ., and story validate ..