benisyouga wo ireru.

を marks the direct object of the verb. In this sentence, 紅しょうが is the thing being added, so it takes を.

• 紅しょうがを入れる
• literally: put in / add red pickled ginger

This is very similar to how English uses the object after a verb, except Japanese shows that relationship with a particle.

Japanese normally puts the verb at the end of the sentence. That is one of the most basic word-order patterns in Japanese.

So instead of English-style:

• Add red pickled ginger

Japanese uses:

• 紅しょうがを入れる
• object + particle + verb

This end-of-sentence verb placement is extremely common.

入れる is in the plain non-past form (also called the dictionary form).

That form can mean different things depending on context, such as:

• to add / to put in as a general action
• will add / will put in
• an instruction style, especially in recipes or manuals

In a recipe, 入れる often sounds like a step in a procedure: add (it).

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

In a recipe, the understood subject is usually:

• you if it is an instruction
• or simply an unspecified person performing the cooking step

So Japanese does not need to say you here. The sentence can naturally stand on its own as a recipe step.

Not exactly in the strong English sense of a direct command like Add it!, but in context it often functions that way.

In recipes, the plain form is commonly used to list steps:

• 切る。
• 混ぜる。
• 入れる。

This gives a neutral, procedural feel: cut, mix, add.

A more direct command would use forms like 入れなさい or 入れてください, but those are less common in simple recipe instructions.

It is read べにしょうが.

A few useful points:

• 紅 here is read べに
• しょうが is usually written in hiragana here, though 生姜 also exists
• this mixed writing is very common in Japanese food vocabulary

So:

• 紅しょうが = べにしょうが

Japanese often mixes kanji and hiragana in everyday writing, especially for food words and common items.

Even though しょうが can be written as 生姜, many writers use hiragana because:

• it is easier to read
• it looks more familiar
• it is common in menus, packaging, and recipes

So 紅しょうが is a very natural spelling.

Because 紅しょうが is one noun, not two separate words in the sentence structure.

Here, 紅 modifies しょうが as part of a compound noun:

• 紅しょうが = red pickled ginger

Then the whole noun phrase takes を:

• 紅しょうがを

So the particle attaches to the full item being acted on, not to the parts inside the word.

No. They are related to placement, but they are different verbs.

• 入れる = to put in / insert / add
  
  • transitive: someone puts something in
• 入る = to enter / go in / be contained
  
  • intransitive: something goes in or is inside
• 置く = to place / put
  
  • more general, often put down or set

In this sentence, 入れる is used because something is being added into something else, such as a bowl, pan, or dish.

The polite form is:

• 紅しょうがを入れます。

In many recipes, though, the plain form 入れる is very common because it sounds concise and instructional.

So both are grammatical, but the plain form fits recipe-step style especially well.

The particle を is pronounced o, even though it is written with the character を.

So:

• 紅しょうがを入れる
• pronounced roughly: beni shouga o ireru

This is a very common thing learners notice early on: the written form is を, but the pronunciation in modern Japanese is usually just o.