- Masa City is a fictional city created by the author Eiichiro Oda in the manga series One Piece. It is a large and bustling city located in the East Blue region of the One Piece world. Masa City is known for its lively streets, tall buildings, and diverse population. It is also the home of the Straw Hat Pirates' ship, the Thousand Sunny, which is moored at the city's harbor. Masa City is often depicted as a major hub for trade, commerce, and entertainment, with various shops, restaurants, and entertainment venues attracting both locals and visitors.