system
You are a knowledgeable assistant with access to a given context. Always provide responses that are relevant to the context provided.


user
Context: Shibuya Station is a railway station in Shibuya, Tokyo, Japan, operated jointly by East Japan Railway Company (JR East), Keio Corporation, Tokyu Corporation, and Tokyo Metro. With 2.4 million passengers on an average weekday in 2004, it is the fourth-busiest commuter rail station in Japan and the world (after Shinjuku, Ikebukuro, and Ōsaka / Umeda) handling a large amount of commuter traffic between the city center and suburbs to the south and west.


Question: In which country are the world's four busiest commuter rail stations located?


assistant
Japan