ruurubukku wo yomu.

ルールブック means rulebook.

It is written in katakana because it is a loanword borrowed from English:

• ルール = rule
• ブック = book

Katakana is commonly used for:

• foreign loanwords
• foreign names
• some onomatopoeia
• emphasis

So this is a very normal way to write rulebook in Japanese.

It is read:

ルールブックをよむ
Romanized: ruurubukku o yomu

A couple of pronunciation notes:

• ルール has a long vowel: ruu-ru
• ブック has a small ッ, which creates a short pause before ku
• 読む is read よむ, not どく in this sentence

So the whole sentence sounds roughly like:

ruu-ru-bukku o yo-mu

を marks the direct object of the verb.

In this sentence:

• ルールブック = the rulebook
• を = marks it as the thing being read
• 読む = to read / read

So ルールブックを読む means to read the rulebook.

You can think of を as showing what receives the action of the verb.

Historically, を was pronounced more like wo, which is why it is still romanized that way in many systems.

In modern Japanese, when を is used as a particle, it is usually pronounced simply as o.

So:

• written: を
• often romanized: wo
• actual pronunciation: o

That is why ルールブックを読む is pronounced ruurubukku o yomu.

Japanese typically uses subject-object-verb word order, so the verb often comes at the end.

In this sentence:

• ルールブック = object
• を = object marker
• 読む = verb

So the structure is:

[object] + を + [verb]

This is different from English, which usually puts the verb before the object:

• English: read the rulebook
• Japanese: rulebook + object marker + read

This verb-final pattern is one of the most important basic features of Japanese sentence structure.

Japanese often leaves out the subject when it is already understood from context.

So ルールブックを読む could mean:

• I read the rulebook
• I will read the rulebook
• He reads the rulebook
• Let’s read the rulebook
• or simply read the rulebook

The exact interpretation depends on context.

This is very normal in Japanese. If the subject is obvious, it is usually omitted.

読む is in the dictionary form (also called the plain form).

This form is used for:

• dictionary entries
• casual speech
• general statements
• labels, instructions, or simple written examples

The verb 読む means to read.

A few related forms:

• 読む = plain/dictionary form
• 読みます = polite form
• 読んだ = read / did read
• 読まない = do not read

So this sentence is using the basic, non-polite form of the verb.

It can mean several of these, depending on context.

The plain non-past form 読む can express:

• to read (dictionary meaning)
• read / reads (habitual or general present)
• will read (future)

Japanese does not mark present and future the same way English does. The non-past form often covers both.

So ルールブックを読む could be understood as:

• read the rulebook
• reads the rulebook
• will read the rulebook
• to read the rulebook

Context tells you which one is intended.

You are right: normal Japanese writing usually does not use spaces.

This sentence would normally be written as:

ルールブックを読む。

Spaces are often added in beginner materials to make it easier to see:

• the noun
• the particle
• the verb

So the spaced version is just a learning aid, not standard everyday writing.

Yes, absolutely.

ルールブックを読みます。 is the polite version.

Compare:

• ルールブックを読む。 = plain / casual
• ルールブックを読みます。 = polite

Both are grammatically correct. The difference is mainly tone and level of politeness.

Use 読みます in:

• formal situations
• speaking to strangers
• classroom speech
• customer service
• polite conversation

Use 読む in:

• casual conversation
• dictionary examples
• notes
• plain-style writing

It is a very natural and understandable way to say it, especially when referring to something literally called a rulebook.

Depending on context, Japanese might also use other words such as:

• 規則集 = collection of rules
• ルール集 = rule collection
• 説明書 = instruction manual (not the same, but sometimes similar in function)

Still, ルールブック is a common and straightforward choice when the item is specifically a rulebook, especially in games, hobbies, or imported products.

。 is the Japanese full stop, like a period in English.

So:

• English: .
• Japanese: 。

It marks the end of the sentence.

In casual writing, especially online or in notes, people sometimes omit it, but in standard written Japanese it is normal to include it.