The Japanese army was known to be the most enthusiastic in hand-to-hand combat during World War II, especially in their night attacks. This unique combination was common especially in the Pacific, which presented challenges for U.S. troops.
The Japanese had a particular preference for hand-to-hand combat in the Second World War, which was combined with their tendency towards night attacks. The psychological effects of killing in combat are explored in various books, particularly from a military mental health professional perspective.
A discussion about the improvisational tactics of enemy forces during war and how it can be surprising to those who are not used to it.