Matsumoto Castle (Matsumoto): Popularly known as the Crow Castle due to its black color, this small castle boasts the oldest donjon (keep) in Japan (400 years old). A moon-viewing room was added in 1635, and exhibited inside the castle is a superb collection of Japanese matchlocks and samurai armor dating from the mid-16th century through the Edo Period. Volunteer guides stand ready for personal tours.

Kyoto Imperial Palace (Kyoto): Home to Japan's imperial family from the 14th century to the 19th century, this palace is praised for its Heian design and graceful garden. Good news for travelers: Guided tours of the palace are free.

Nijo Castle (Kyoto): One of the few castles built by the mighty Tokugawa shogunate as a residence rather than for defense, Nijo Castle is where the shogun stayed whenever he was in Kyoto. It's famous for its creaking floorboards that warned of enemy intruders. The castle is considered the quintessence of Momoyama architecture.

Katsura Imperial Villa (Kyoto): Built in the 1600s by a brother of the emperor, this villa and garden are considered to be among the best -- if not the best -- in traditional architecture and landscape gardening. More than anyplace else, the villa illustrates the life of refinement enjoyed by 17th-century nobility, when leisurely pursuits included such activities as moon viewing.

Osaka Castle (Osaka): Although just a reproduction of what was once the mightiest castle in the land, Osaka Castle still impresses with its sheer size. Inside you'll find a high-tech museum detailing the life and times of Toyotomi Hideyoshi, the warrior general who built the castle.

Himeji Castle (Himeji): Said to resemble a white heron poised in flight over the plains, this is quite simply Japan's most beautiful castle. With its extensive gates, moats, turrets, and maze of passageways, it has survived virtually intact since feudal times. If you see only one castle in Japan, make it this one.

Matsue Castle (Matsue): This 17th-century castle is one of Japan's few remaining original castles (not a reconstruction). It features a five-story donjon with samurai gear and artifacts belonging to the ruling Matsudaira clan.

Matsuyama Castle (Matsuyama): Occupying a hill above the city, this is also one of the few original castles left in Japan. It boasts good views over Matsuyama from its three-story donjon as well as a collection of armor and swords of the Matsudaira clan.

Kumamoto Castle (Kumamoto): Although a ferroconcrete reconstruction not nearly as huge as the original, this massive castle is still an impressive sight, especially at night when it's illuminated. It's famous for its curved walls, which made invasion virtually impossible. The interior houses a museum with palanquins, armor, swords, and other artifacts of the former ruling clans.