What cultural and political changes introduced during the Ashikaga period had a long-lasting effect on Japanese history and civilization? By what measures did Oda Nobunaga Toyotomi Hideyoshi and Tokugawa Ieyasu manage to unify the realm and what were the limits to their achievement of unification? In what ways and to what extent (if at all) did the role and the ambitions of the samurai change from the time just prior to the establishment of Tokugawa rule through the early decades of the Tokugawa era in the 17thcentury. How if at all did the samurai role and ambitions or self-understanding then change through 18thand 19thcenturies? How did Japanese culture change during the Tokugawa period? What was the importance of Confucianism to the culture of Japan?