Serving as the main entrance of Imperial Palace, Kokyogaien is an eminent place to get your bearings before entering the main grounds of the palace.
Featuring some of the Palace's yaguras (watching towers), bridges, and gates, visitors can get a preview of what is the inside from this section of the National Garden. And once they have wrapped up their journey around the Emperor's residence, this garden serves as an agreeable resting area before continuing their sightseeing in Marunouchi.
More info
Find out more about Imperial Palace.