The particle -ni [wip]

THE PARTICLE NI

-ni is one of those particles in Japanese that annoyingly evades simple description. Other particles, like -wa, or -o, are beautifully efficient in their purposes- Wow! Use this to mark the subject! Woah! This one marks the direct object! Japanese is so fun and easy!

Nope, -ni, at first glance, seems to be the particle Japanese uses when it doesn't have any better particle to use. It can mark the indirect object. But probably not. It could mark the direct object. But probably not. You might be able to translate it as "to," or "in," or some other preposition. But probably not. Noticing a theme here?

There are ways of unifying the uses of -ni into a single "target particle;" Tae Kim takes this approach on his [excellent and highly-recommended] Guide to Learning Japanese. The phrasing is slightly confusing, but it's true: -ni tends to mark some sort of direction or specification in most scenarios. Thing is, just that information on its own is useless- direction? Specification? What kinda grammatical term is that supposed to be?

Instead of unifying, perhaps it's better to consider -ni as the case-by-case particle: its uses, functions, and therefore translations, are so varied you might as well think of it as many particles that just coincidentally sound and are written the same.

THE LOCATION -NI
-ni can be used to mark location. "But wait! Don't you use -de for marking locations?" And yes, that's true. But you also sometimes have to use -ni. The difference lies in the verb.

You've got action verbs and state-of-being verbs. Action verbs are more, well, active; eating sketchy takoyaki at 2 a.m., vomiting violently, calling 911- while states-of-being are more passive. They just describe, well, how things are- aru and iru, the existence verbs, are two of the most common. You've also got sumu- to live; hataraku- to work (at a place); and so on. Also usually included in this category are -te imasu verbs, the progressives; these are seen in Japanese grammar as states-of-being.

You're probably used to using -de for locations, but this only works for actions. With states-of-being, you have to use -ni.

This is the -ni with which Japanese accomplishes most of Indo-European preposition functionality: paired with location nouns, an existence verb, and possibly a relative clause. Ue-ni, tonari-ni, ushiro-ni- you could even include tame-ni in the same category.

THE DIRECTION -NI
-ni is commonly translated as "to," which can be true, but in context, of course: -ni often specifies direction, with verbs with which a direction would make sense. The list of verbs with which you can use directional -ni can be fairly intuitive, but unfortunately, you've just gotta learn them as you go along.

Some of the more common ones:
-iku- to go; kuru- to come; kaeru- to go home: verbs of going and of motion.
-ageru- to give; etc.: verbs of giving- and slightly less intuitive, the verbs of receiving.
-okuru- to send
-au- to meet: makes sense when you think about it, but doesn't parallel English usage.
-katsu- to win; makeru- to lose: doesn't make sense when you think about it. Just learn it as another Japanese oddity.

THE TIME -NI
This one's simple- whenever you'd like to specify a time, just throw in a time-ni, keeping in mind the generic-time/specific-time distinction. It's worth noting that this usage combined with -ni's other usages makes -ni one of the few particles capable of being used multiple times in one clause- apart from -to and -mo, of course, with which you can make lists.

THE GENERIC PREPOSITION -NI
From here on down, the usages of -ni get smaller and more isolated, so this is a blanket term of sorts for a bunch of more isolated usages of -ni. Usually, these smaller ones conveniently correspond with one English preposition.
- formal stem-ni + verb of going: going to a place to do something.
- lalala