It has been said that, in either of the kanjo ceremony in Taizokai (Realm of the Womb) and that in Vajradhatu, the flower Kukai threw dropped on the laid Mandala (a diagram that depicts Buddhist deities according to certain geometric formats and illustrates the Buddhist world view), connecting him with Dainichi Nyorai (Mahavairocana) in the two areas (or two realms).
ちなみに胎蔵界・金剛界のいずれの灌頂においても彼の投じた花は敷き曼荼羅の大日如来の上へ落ち、両部（両界）の大日如来と結縁した、と伝えられている。