It is a common misconception that the Chinese and Japanese languages are related. Never mind that Chinese is just a VERY general term for perhaps hundreds of dialects spoken in China that at times are barely intelligible to one another, it is simply not true. read more
The Chinese people are thus more related to the Caucasians of Haplogroup R1 (Y-DNA), via their common ancestor Haplogroup MNOPS (Y-DNA). The perception that Chinese and Japanese people look similar may be due to the similar latitude and/or environments in which they evolve in the more recent past. read more
As noted by Mr. Corley, technically they are not related, but because the later two language borrowed heavily on Chinese Words early in their development (and in modern times the Chinese also used some of the words the Japanese invented, especially regarding western stuff) there are some connections. read more