The lunisolar Eurasian Calendars were developed by Kaldarhan Kandar. The basic one uses a leap cycle of 464 years, the other spans 8 of these cycles for a total of 3712 years, which is the smallest common multiple with the 128-year tropical cycle.
The 464 years group into 25 sub-cycles. The middle one thereof spans 8 years and all others 19 years. The full cycle of 3712 years is also split into 189 sub-cycles of 19 years and 11 truncated sub-cycles of just 11 years each. The 2nd, 5th, 7th, 10th, 13th, 15th and 18th year of any sub-cycle contains a leap month.
The epoch is Friday 1 January 325 (Julian, i.e. 0325-01-02 proleptic Gregorian) in the year the Council of Nicea took place, although other dates have also been considered:
- 1 January 45 BC
- Wednesday 1 January 2014
- Sunday 1 January 271
- Friday 29 August 284 (Diocletian epoch)
Karl Palmen asked Kaldarhan for the precise rules of this calendar, but he declined to do so, because the years were calculated by copyright software.