There are more books published in Japanese on how to write novels than ever before, and of course I have read a few. Japan, a nation of poets, has more published authors per capita than most other countries, and as with most other first world countries, there seems to be more writers than readers. Of course there are some translated works, notably How to Write Best Selling Fiction by Dean R. Koontz which seems to be mentioned often, but most of the books are written by Japanese authors tackling specific issues relating to writing in Japanese.
Most of these books tell you about point of view, “show don’t tell”, and references to Campbell’s “hero’s journey”. They usually teach you about the four act plot structure instead of the three act plot structure. But they also show you some other elements that are not often found in writing instructions in English.
One of the things Japanese books on writing talk about at length is the rules governing conventions. For example, if you are writing a spy thriller in the vein of James Bond’s adventures, it is perfectly permissible that the main character is an expert in every martial art known to man, can fly a helicopter, operate a power shovel, navigate a submarine, defuse a time bomb, speak the most obscure foreign language with utmost fluency, build a satellite communications equipment out of old vacuum tubes and wire hangers, perform emergency surgery with a steak knife, be acquainted with every foreign dignitary on Earth, survive frequent torture, be an irresistible ladies-magnet, and never have a wrinkle in his tuxedo. However, he cannot be a graduate of Hogwarts, or summon his patronus with a magic wand. If you are writing something like an Hercule Poirot mystery, it is perfectly fine that your detective runs into his English friend by coincidence in Egypt, that eight different people with different motives for murder just happen to be taking a trip on the same boat, that the detective who just happens to be loitering about aimlessly chances to eavesdrop on every relevant conversation spoken over the course of a week but never bumps into the murderer killing a series of victims, or that he just happens not to notice the one clue that might have solved the mystery five murders ago. But it is not okay for the murderer to be a vampire, a werewolf, a witch, a space alien, or the Devil.
Every make believe world exists within its own boundaries. That is why even though Harry Potter lived in the present world, he never looked up anything on the internet. There are rules governing each universe. In case you did not notice, it is quite ironic that James Bond and Jason Bourne armed with just one pistol can win a shootout against a platoon of bad guys with assault rifles, but they are never supposed to use any kind of magic. There are things that are supposed to happen in your story universe, and there are things that are not supposed to happen.
Imagine reading Stephen King’s horror story, following a single-parent family taking a series of wrong turns as they try to evade an insane serial killer. Just when you thought the mother and her children, cornered inside a decrepit mansion, were about to meet their death, Superman flies in through the window and saves the day. You can see that would be an incongruous intrusion. The book would either turn into meta-fiction or a comedy.
And this does not apply only to story elements and plots, but also to vocabulary and writing styles. 17th century pirates can be the most bestial savages imaginable, but they never say “Fuck you”. Not even the narrator is allowed to mention telephones, movies, or cars. Young women are “wenches” not “bitches”. Men are “comely” not “hot”. It is not scary to be in a position of wealth and power, but uneasy rests the head that wears a crown.
It is so strange that books that teach you writing that are published in English seldom tell you to write within the conventions of your genre. In fact, Western writers seem to take pride in defying the conventions of their genre. But there are limits to that, and when you read some amateur, self-published, ebooks, incongruous prose is one of the most often seen mistakes.
If you want to write a story about secret agents battling vampires, or wizards and witches communicating with email, you are free to try, but even those worlds would have rules of their own that cannot be broken. You have to define those rules early and stick to them. Western attitudes on creativity makes it difficult to admit to these things, but in a way, it is just as important to stay inside the box as it is to think outside.