Nijo castle dominates the center of Kyoto. Built in 1603 by Togukawa Ieyesu, the first Shogun of a united Japan, it served as his official audience hall. Intended to impress visitors, the showy castle is more palace than fortress, with defenses designed for looks rather than combat. The cautious Shogun knew that the most likely avenue of attack would be from treachery within, so he had hidden guards posted in the rooms and "nightingale" floors that squeak at the lightest pressure. Regardless, the Shogun spent only a fraction of his time here, preferring to remain in the east where the real power centers were coalescing around Edo (Tokyo).