What is Considered Chinese Nin-Jitsu and the Predecessor to the Japanese Ninja?

Ever since I got into the Mortal Kombat franchise, I had always wondered how the creators have gotten their inspiration for the ninja clan known as the "Lin Kuei". I had always wondered where the inspiration from Lin Kuei came from. For one, I had known that this was a name that a group of programmers from the United States were able to create from the top of their heads.

I did some real digging as it seemed that there is an actual Lin Kuei. Rumors say that they were the predecessors to Japanese ninja of Japan. However, the claims are backed by no concrete evidence. It's unknown if the various schools of Nin-Jitsu had descended from the Lin Kuei. Currently, there is also no written evidence if the Lin Kuei had even existed.

In short, the Lin Kuei was the Chinese equivalent to ninjas. A member of the Lin Kuei would be considered a Chinese ninja. They would have their own form of Chinese Nin-Jitsu called "An Ch'I". But again, there's no conclusive evidence that there is an actual style known as An Ch'I. In order to find the information, one would have to invest a lot of time and money to go in-depth in China's history. But it's easier said than done, though.

A good portion of China's history could be considered lost due to the Japanese and Western occupation of the country before and during World War II. And then the Communist regime would take over after World War II further erasing a bit more of China's history.

However, the inner circles of the ninja do accept that most of the methods of Nin-Jitsu had actually come from China. It is pretty logical as most of the Eastern martial arts had come from the various styles of Kung-Fu. Without Kung-Fu, there would be no Karate, Jiu-Jitsu, Tae Kwon Do, or Hapkido. In short, you cannot discount the massive contributions the Chinese have made in the creation of many of the fighting styles that are existent in today's world.