Yamashita Park (山下公園, yamashitakouen) is located right next to Yokohama China Town. The Park is attached Yokohama Port, so in Night time, you would have a great night scene of Minato Mirai 21 which is the one of the best night scenes in Japan.
Tourist Info.
Parking and restroom are available. There are many benches for viewing the port.
Access
0. at Tokyo Station
1. take JR Keihintohoku Line to Kannai (41min.)
2. walk east (10min.)
1 hr.
Let's learn MJER Iaijutsu. 
映画好き集まれ！ 
Yamashita Park is one of the famous dating spot because it has great night scene of Minato Mirai 21. In the center of the park, there is the stone figure and fountain which given by San Diego City. At the pier, Hikawamaru ship is tied up for visitors. When you are in Yokohama, check this great night scene offered by Yamashita Park.