The Chinese haven't forgotten either. Every time that there is a spat between the Chinese and Japanese governments Chinese TV rolls out the footage of the Nanking Massacre. There is no shortage of photographic records; almost all taken by the Japanese themselves, so if you want to be sickened, Google it.
One Japanese newspaper, the equivalent of a UK tabloid rag, kept it's readers up-to-date with a competition between two Japanese army officers as to who was leading in a competition to see who was beheading the most Chinese.
They were both past a century.