What is "naka-ku"

Naka-ku , meaning "Central District", is a common ward name in many Japanese cities.

• Naka-ku, Hamamatsu, in Hamamatsu
• Naka-ku, Hiroshima, in Hiroshima
• Naka-ku, Nagoya, in Nagoya
• Naka-ku, Okayama, in Okayama
• Naka-ku, Sakai, in Sakai, Osaka
• Naka-ku, Yokohama, in Yokohama