Learn Hardcore Japanese: goukaku no tame ni, mainiti nihongo no bunpou wo benkyousimasu. - In order to pass, I study Japanese grammar every day.

合格（ごうかく）
Noun: passing / success (in an exam, test, selection, etc.)
の (after 合格)
Particle linking a noun to another noun-like word. Here it connects 合格 to ため, making 合格のため = for the sake of passing.
ため
Noun meaning sake, purpose, benefit, reason. Often used in patterns to mean for / in order to / because of.
に (after ため)
Particle that attaches to ため in the set phrase 〜ために. Together ために means for the purpose of / in order to.
、
Comma. Separates the purpose clause from the main clause.
毎日（まいにち）
Adverb meaning every day.
日本語（にほんご）
Noun: the Japanese language.
の (after 日本語)
Particle linking 日本語 to 文法: 日本語の文法 = Japanese grammar / the grammar of the Japanese language.
文法（ぶんぽう）
Noun: grammar.
を
Object marker. Marks what is being studied: 文法を = (the) grammar (as the direct object).
勉強します（べんきょうします）
Verb (polite form): to study → I study / will study.
Literally: do study (since 勉強 is originally a noun study, and します is do).

Overall structure:
[合格のために]、[毎日][日本語の文法を][勉強します]。
For the purpose of passing, I study Japanese grammar every day.

Why is there の after 合格? Could I say 合格ために instead?

You need の here. The pattern is:

Noun + の + ため(に)

So:

合格のために ✔️
合格ために ✖️ (unnatural / ungrammatical)

Reason:

ため is a noun, and when one noun modifies another noun in Japanese, you typically use の:
- 子どものために = for the sake of children
- 健康のために = for (my) health
- 勝利のために = for victory

In this sentence, 合格 is a noun (passing), and ため is also a noun (sake/purpose), so Japanese uses の to connect them: 合格のため.

Can I also say 合格するために? Is there any difference from 合格のために?

Yes, you can say both:

合格のために、毎日日本語の文法を勉強します。
合格するために、毎日日本語の文法を勉強します。

Both mean essentially I study Japanese grammar every day in order to pass.

Differences:

Form
- 合格のために
  uses 合格 as a noun: for the sake of passing.
- 合格するために
  uses 合格する as a verb: in order to pass.
Nuance
- In everyday conversation, they are extremely close in meaning.
- Verb + ために (合格するために) feels slightly more explicitly action-oriented, because you can see the verb する.
- Noun + の + ために (合格のために) feels a bit more compact / nominal, and is very common in slogans, written language, and set phrases:
  - 成功のために
  - 将来のために
  - 健康のために
When another particle is involved:
- If you say what you’re passing, it’s usually:
  - 試験に合格するために、毎日勉強します。
    (In order to pass the exam, I study every day.)
    The verb form fits more naturally here.

For your original simple sentence, both 合格のために and 合格するために are fine and very natural.

What exactly does ために do here? Is に the same as the usual に for time/place?

In 合格のために, ために is functioning as a set expression meaning for the purpose of / in order to / for the sake of.

ため = sake / purpose / reason
に = particle that attaches to ため to form ために

So ために marks a purpose clause:

合格のために
→ for the purpose of passing
健康のために運動します。
→ I exercise for my health.
日本で働くために、日本語を勉強しています。
→ I study Japanese in order to work in Japan.

Is this に the same as time/place に?
Grammatically they come from the same particle, but in ために it’s best to think of it as part of a fixed grammatical pattern:

[Verb dictionary form] + ために
[Noun + の] + ために

It doesn’t mean at or to here; it simply turns ため into the phrase for the sake of / in order to.

Could I drop に and say 合格のため、毎日日本語の文法を勉強します。?

Yes, that is also correct:

合格のため、毎日日本語の文法を勉強します。 ✔️

Differences in nuance:

合格のために
Very common in speech and writing; neutral.
合格のため、 (without に)
Sounds a bit more formal / written, and in many contexts leans slightly toward a reason reading (because of) rather than a clear purpose, depending on context.

In your sentence, both are normally understood as purpose:

(合格のため(に))、毎日日本語の文法を勉強します。
→ I study Japanese grammar every day in order to pass.

For everyday spoken Japanese, keeping に (→ ために) is safer and more natural.

What role does 毎日 play in the sentence, and where can it go?

毎日 is an adverb of time meaning every day. It tells you how often you study.

Japanese adverbs are quite flexible in position. All of these are natural, with slight shifts in emphasis:

合格のために、毎日日本語の文法を勉強します。
Neutral: Every day, I study Japanese grammar in order to pass.
合格のために、日本語の文法を毎日勉強します。
Puts a bit more focus on the studying itself happening every day.
毎日、合格のために日本語の文法を勉強します。
Emphasizes every day at the start.

Grammatically they are all fine. Position mainly affects rhythm and emphasis, not meaning.

Why is there の between 日本語 and 文法? Could I say 日本語文法 instead?

日本語の文法 is:

日本語 = Japanese (language)
の = connects two nouns
文法 = grammar

So 日本語の文法 = the grammar of the Japanese language / Japanese grammar.

About 日本語文法:

日本語文法 is also used, especially in titles, academic contexts, books, and technical writing, where compound nouns are common.
- e.g. book title: 日本語文法入門 = An Introduction to Japanese Grammar

Nuance:

日本語の文法
- More natural and common in ordinary sentences and conversation.
日本語文法
- Feels more like a technical term or title, a single compact noun.

In your sentence, 日本語の文法を勉強します is the most natural everyday way to say I study Japanese grammar.

Why is 文法 marked with を, not が or は?

を marks the direct object of a verb — the thing that is directly acted on.

文法を勉強します。
→ (I) study grammar.
Here, 文法 is what you study, so it takes を.

Compare:

を → direct object:
- 日本語を勉強します。 = I study Japanese.
- 本を読みます。 = I read a book.
が → often marks the subject or something being described / identified:
- 文法が難しいです。 = Grammar is difficult.
は → topic marker; what the sentence is about:
- 文法は難しいです。 = As for grammar, (it) is difficult.

In 日本語の文法を勉強します, 文法 is not the topic or subject; it is the direct object of 勉強します, so を is the correct particle.

Why is the verb in the ます form (勉強します) instead of plain 勉強する? Can I use 勉強する here?

Japanese verbs have at least two basic styles:

Polite style: 勉強します
Plain style: 勉強する

In your sentence:

勉強します is the polite form, suitable for:
- talking to teachers
- talking to people you don’t know well
- writing in textbooks, formal writing, etc.

You can grammatically say:

合格のために、毎日日本語の文法を勉強する。

This is:

Correct, but plain style, more natural:
- when talking to yourself
- in casual writing (like a diary)
- with close friends (if the rest of your speech is also plain)

Important:
Don’t mix polite and plain styles randomly in the same conversation. Choose 勉強します or 勉強する based on how polite you want to be, and keep it consistent.

Is the word order fixed? Could I move 合格のために or 毎日 to other places?

Japanese word order is relatively flexible, especially for adverbial phrases like 合格のために and 毎日.

All of these are grammatical (with slight differences in emphasis):

合格のために、毎日日本語の文法を勉強します。
→ Purpose first, then frequency, then object + verb.
毎日、合格のために日本語の文法を勉強します。
→ Emphasizes every day by putting it first.
日本語の文法を、合格のために毎日勉強します。
→ Focuses a bit more on what you’re studying.

Natural constraints:

The main verb (勉強します) must come at the end.
The object + を (日本語の文法を) is usually close to the verb.
Purpose phrase 合格のために is most naturally before the main clause, but can move within reason.

So word order is somewhat flexible, but the verb at the end and particles marking roles are what really matter.

What’s the difference between ために and ように in similar sentences, like 合格できるように毎日勉強します?

Both ために and ように can introduce something like a goal/result, but they have different typical uses.

ために (purpose, intention)
- Pattern: Verb dictionary form + ために
  or Noun + の + ために
- Emphasizes a conscious purpose / intention of the subject.
Examples:
- 合格するために、毎日日本語の文法を勉強します。
  → I study every day in order to pass.
- 健康のために、野菜をたくさん食べます。
  → I eat lots of vegetables for my health.
ように (so that, in such a way that)
- Often used with:
  - potential verbs (できる, 分かる, 行ける, etc.)
  - states or situations not fully under direct control
- Feels slightly more indirect / objective / hopeful.
Example:
- 合格できるように、毎日勉強します。
  → I study every day so that I can pass. (nuance: I’m aiming for the ability / situation of being able to pass)

Nuance difference between the two examples:

合格するために、毎日勉強します。
→ Clear, direct statement of purpose: passing is your goal.
合格できるように、毎日勉強します。
→ Emphasis on creating the conditions / ability to pass, a bit softer and more “so that I’ll be able to pass”.

Both are correct; the original sentence with 合格のために is firmly in the purpose camp.

Does 合格のために、毎日日本語の文法を勉強します。 imply I’m only studying grammar, or could I be studying other things too?

The sentence literally states:

I study Japanese grammar every day in order to pass.

It only mentions grammar, but it does not strongly imply that grammar is all you study. It just says:

Among the things you do to pass,
you (at least) study Japanese grammar every day.

If you wanted to make it sound like grammar is the only thing:

合格のために、毎日日本語の文法だけを勉強します。
→ I study only Japanese grammar every day in order to pass.

Without だけ, it’s simply describing one specific, regular effort you make toward passing.