- ID: YYBW-005
- Status: Decided
- Date: 2026-04-13
- Scope: YY Branching World / YY's World evolution
- Depends on: YYBW-003, YYBW-004
- Supersedes / clarifies: Clarifies use of real dates and historical replay
- Museum lineage: SK-009
Context
The event engine evolved from generic world events to a stronger idea: use real-world events as seeds, abstracted enough to remain universal but still tied to actual dates. Later, historical rewind emerged: start in a past month or period, seed the world through known history, and replay to today.
Decision
Each root uses a shared event stream tied to real dates. Events are abstracted from real-world conditions, but keep a real date anchor for inspection. The system must support historical rewind/replay from selected prior periods.
Why
This adds:
- shared temporal reference
- inspectability against lived history
- stronger narrative pacing
- a way to ask 'what would YY have done during that period?'
- high replay value
Alternatives considered
- Completely fictional event streams — rejected as less resonant and less inspectable.
- Literal news reproduction — rejected because it narrows the world and creates brittle specificity.
- No rewind, forward-only — rejected because history offers immediate depth and controlled experiments.
Reversals / scars preserved
- Early excitement about 'the world rolls the dice today' remains central.
- A later refinement insisted on abstraction instead of raw literal news.
- The historical-replay addition turned the system from only live simulation into backtestable causality.
Consequences
- Event records need real_date, story_day, abstraction layer, and source provenance.
- Users should be able to inspect events by date and compare reactions across branches.
- Content moderation/editorial curation remains important because real-world events can be heavy.
Invariants preserved
Timestamping is explicit; Explainability through event alignment; Survivability through abstracted storage; Discipline through abstraction boundaries.
Freshness boundary
Requires periodic editorial judgment as real-world event sourcing evolves.