Early on, Japanese Castles were built mainly for military purposes and were used in times of war, but later on, they became more of a display of the castle's lord's (daimyo) power. Tenshus became larger and their roof's military uses became decorative as well. The higher and larger a castle's tenshu was, the number of people who could see the daimyo's power increased. It was a grand symbol for many historic figures including Toyotomi Ieyasu and the Tokugawa family. Of course, aside from the military uses and artistic skills placed into the design of the tenshu's roofs, ancient beliefs and superstition was incorporated as well.

Not only was the castle's exterior design a form of displaying power, so was its interior. Any lord would welcome a visit from higher authority. To make the interior fit for this purpose, different rooms were built according to ancient seating arrangements. Beautiful paintings and murals were displayed on walls, sliding doors, etc. Valuable objects were also displayed. Of course, the greatest things were always in the highest ranking room, whether or not the owner of castle would stay there. The Japanese had the utmost respect for higher authority.

Not only were the interior of castle buildings a display of artistic skills, but even the interior of the castle grounds. The Japanese regarded gardens as an art because of the belief that its designs held were passed down from ancient times. The different parts of a garden represented different things in life and the thought and precision that went into the placement of everything in the garden was most detailed.