Lets discuss Wano Country.
The country in which the Legendary Samurai Ryuuma hails from is known as a powerful country called Wano. Wano being based off isolated Japan is strong enough to keep the World Government and possibly the Yonkou from ruling over them. Wano is also the first named location in the One Piece Series, being named several years before One Piece first came out in Oda's one shot Monsters.
What is your intake/theories/predictions/knowledge on this subject?