I've slightly more familiarity with the japanese.
- Japan's fairly homogenous, isolated & xenophobic, whereas the chinese people comprise a variety of eastern ethnic groups.
- Many japanese people believe in shinto, revolving around demons and gods of folklore and the ubiquitous presence of spirits. It oft is reflected in their works. China is officially atheistic, with less focus on religion as much as philosophical wisdom contained in buddhism (shared by japan, with modifications), taoism, confucianism.
- China is a communist regime filled with surveillance, japan's closer to western capitalism & ideals aside from the emperor (which is not too far from parallel monarchs either; slightly more genuine reverie, I guess).
- Japan has very strict rules regarding social conduct & hierarchy (eg uchi soto, levels of politeness) which are fairly extreme by any relative measure.
- Whilst both countries seem to avail less leisure than work time, japanese people take pride in honing skills of craftsmanship as part of their defining traits, seeking to achieve a cycle of mastery and innovation for many years regardless of the position; apparently china's closer to the west in that regard.