Vimshottari means “120-year” — the cycle’s total length. Each of the nine grahas rules a fixed share: Sun 6, Moon 10, Mars 7, Rahu 18, Jupiter 16, Saturn 19, Mercury 17, Ketu 7, Venus 20. The cycle is keyed to the nakshatra your Moon occupied at birth.

Ashtottari is a 108-year, 8-lord cycle (no Ketu) attributed to Satya Acharya. Several classical schools — particularly in Bengal and parts of North India — read Ashtottari alongside Vimshottari for nuance.

Yogini is a 36-year cycle of eight feminine deities (Mangala, Pingala, Dhanya, Bhramari, Bhadrika, Ulka, Siddha, Sankata), each with a planetary lord. Years ascend 1, 2, 3, …, 8. Sources: Sanjay Rath’s Yogini Dashas (1999); Charak’s Predictive Astrology Ch. 18.

Chara is computed here as a fixed Jaimini sign-based scheme. Each rashi rules 9 years (movable), 8 (fixed), or 7 (dual) — 96 years in all — whatever the chart; the chart only picks the starting rashi. The cycle starts at the lagna’s rashi and runs zodiacally; the rashi’s natural lord is the mahadasha lord. It is not the Chara dasha of K.N. Rao or P.V.R. Narasimha Rao, whose years come from each sign’s lord and whose direction depends on the chart. Antardasha breakdown is not exposed here — the mahadasha is the dominant Jaimini timing layer.

Narayan applies the Jaimini parity-direction rule (Upadesa Sutras Ch. 2) on top of the Chara skeleton: an odd-padi (vishama-pada) lagna sends the cycle forward (zodiacal); an even-padi (sama-pada) lagna sends it backward. By default the durations are the fixed Chara-modality years (9/8/7) with natural sign-lords; the Variable duration rule switches to the sign-to-lord-distance durations of Sanjay Rath’s Narayana Dasa (Sagar Publications), where a lord in its own rashi gives 12 years.