This article reappraises the interaction between Saicho (767-822) and Kukai (774-835), founders, respectively, of the Japanese Tendai and Shingon schools of Buddhism. This new appraisal is based on the histori cal conditions in which these two men sought to introduce new types of Buddhism at the close of the age of Nara Buddhism, rather than on the conventional, idealized characterizations of the two figures as the founding fathers of their respective schools. What emerges is the unbridgeable differ ence between Saicho and Kukai in their interpretive strategies for delineat ing the role of esoteric Buddhism (Mikkyd) in establishing a new order in the early Heian Buddhist community, a difference that presented itself as a persistent tension that underlay saicho ys alliance with Kukai from the very outset of their relationship.