Love to Know Feng Shui explains that a Japanese dragon is a mythological creature similar to Chinese dragons but with several differences. A Japanese dragon has only three toes on its feet. It also features spikes on its back. Like Chinese dragons, they are more serpentine than European Dragons.
The most common type of Japanese dragon is called the Ryu or Tatsu and is descended from Chinese dragons. While Chinese dragons are often associated with the rain, Japanese dragons are more associated with the sea because Japan does not have as many droughts as China. The Ryu is often used as an emblem of the Emperor of Japan.