needs sauce!
the BA and KA (Egyptian) or Yin and Yang (Chinese) connection
4 year cycles - Ancient Egyptian - Nostradamus
taking as an example the history of Russia over the past century:
1901, add on four years gives 1905, and continuing 1909, 1913, 1917, 1921, 1925, 1929, 1933, 1937, 1941, 1945, 1949, 1953, 1957, 1961, 1965, 1969, 1973, 1977, 1981, 1985, 1989, 1993, 1997
Anyone with a knowledge of history will immediately notice that almost all the above dates are connected to very important milestones in the destiny of Russia. It should be stated at once that this scale applies not only to Russia.
2001, 2005, 2009, 2013, 2017, 2021, 2025 and so on
https://www.bibliotecapleyades.net/ciencia/ciencia_wandshorus02b.htm