The 600-Year Yuga Cycle is an old Vedic and Sumerian idea about time repeating on a fixed schedule.
It treats history as running in a destruction cycle that comes around every 600 years, which equals 216,000 days.
The count is anchored to the Great Flood dated at 2239 BCE, and this 600-year rhythm lines up with another recurring pattern the engine tracks, the 138-year Phoenix cycle.
It's one of the recurring-timeline frameworks the engine uses to test whether catastrophes fall on a predictable repeating schedule.