Chen = Chinese family name
Kenichi = Japanese given name
Is he half Chinese and Japanese?
What’s really confusing is that sometimes the Japanese will reverse it–even when they are speaking Japanese–if they are speaking to a foreigner. I’ve been confused a couple times when someone did that. Most of the time, it’s not a problem since a lot of family names tend to repeat; you get familiar with the most common ones. Occasionally, the lack of consistancy in reversing or not reversing the order will cause some kind of mixup though. Pain in the butt. I’d prefer it if everyone just completely forgot about the whole non-Japanese-do-it-this-way thing.
I usually go by my family name for two reasons: I resent being called by my first name in a situation where, even in the West, I would be called by my family name.
(“John-sensei [not my real name] I am Yamamoto. I am the new teacher. I will be working with you.”
“Hey, Kenji Yamamoto, nice to meet ya. You don’t mind if I call you Ken-chan do you?”
<sigh> Sarcasm and irony do not register most of the time. I usually get the Confused Blink™ in response to an exchange like this.)
The other reason is that my family name is a lot easier for Japanese people to pronounce 
I go by my first name professionally and privately for several reasons, one being that my first name is shorter and easier.
I’ve had a problem where one of the other managers insists on introducing me by last name to people, even after I insisted on being called by my first name. 
This person would also introduce people to me in English, even though that person doesn’t speak English and I speak Japanese. The recepient is then left confused, not knowing what to do.
After checking on Wikipedia, I’m not entirely sure. His father is Chen Kenmin, who is apparently considered the father of Szechwan cooking in Japan. The article on Kenichi indicates that he was born in Japan, but doesn’t say whether his father was also born in Japan or China. Googling “kenmin” turns up sites with .jp domains almost exclusively, which leads me to believe that it’s a Japanese name; is the name used in China as well? In any case, there’s no mention of Kenichi’s mother at all, so I’ve no idea where she’s from.
My wife is Japanese and when she talks to her friends she refers to herself by her family name.