Nichien seems to have been known for his activities in the field of Rokumei, rather than Suiyodo, however, as in "Nichureki" (Dual History), he was described not as a Sukuyoshi (master of an astrology based on the Sutra of constellations and planets) but as a Rokumeishi (teller of one's destiny) and well informed about Rokumei (one's lot) which tells fortunes by examining one's physiognomy or date of birth.
ただし、『二中歴』には、日延は宿曜師ではなく、人の骨相や生年月日から人の運命を占う禄命に通じた禄命師として扱われており、宿曜道よりも禄命の分野での活躍が知られていたようである。