kono hutatu no kaban nara, kuroi hou wo kaimasu.

この 二つ の かばん means these two bags.

Here is the structure:

• この = this / these
• 二つ = two
• の = links the number phrase to the noun
• かばん = bag

So the whole phrase is literally something like these two bags.

A few important points:

• この must come directly before the noun phrase it modifies.
• 二つ の かばん works like two bags.
• Putting them together gives この 二つ の かばん = these two bags.

二つのこのかばん sounds wrong because この normally comes right before the noun, not after a number phrase.

The の connects 二つ to かばん.

So:

• 二つのかばん = two bags

This is a very common pattern when using native Japanese numbers like:

• 一つのりんご = one apple
• 三つの箱 = three boxes

You may also hear counter-based expressions such as:

• かばんが二つ = there are two bags
• 二個のりんご = two apples

In this sentence, 二つのかばん is a noun phrase, so the の helps build two bags as a unit.

なら means something like:

• if it’s
• if we’re talking about
• when it comes to

So:

• この二つのかばんなら、黒いほうを買います。

means something like:

• If it’s between these two bags, I’ll buy the black one.

It sets a condition or topic: among these two bags / in that case.

This なら often gives the feeling of choosing or judging based on a specific situation.

Because 黒い is the -i adjective meaning black.

• 黒いかばん = a black bag

In this sentence, 黒い modifies ほう, not directly かばん:

• 黒いほう = the black one / the black side

黒 by itself is a noun, meaning blackness / the color black, and it cannot normally replace 黒い here in standard basic usage.

So 黒いほう is the natural form.

ほう is often used when comparing two things, and it means something like:

• the one
• the side
• the option

So:

• 黒いほう = the black one

This is very common in Japanese when choosing between two items:

• 大きいほう = the bigger one
• 安いほう = the cheaper one
• 静かなほう = the quieter one

In your sentence, the bags are already mentioned, so Japanese does not need to repeat かばん. ほう stands in for the one of the two.

Because Japanese often avoids repeating a noun when it is already clear from context.

Instead of saying:

• 黒いかばんを買います

the sentence says:

• 黒いほうを買います

This sounds more natural when choosing between two things. It specifically means the black one (out of the two).

So ほう is useful because it avoids repetition and emphasizes the comparison.

を marks the direct object of the verb 買います.

• 買います = buy
• What do you buy? → 黒いほう

So:

• 黒いほうを買います = I will buy the black one

Even though ほう means one / option / side, it still functions as a noun here, so it can take を like other nouns.

Yes, この is the kono form from the ko-so-a-do series and is usually taught as this.

But in English, when it modifies a plural idea like two bags, it is naturally translated as these:

• このかばん = this bag
• この二つのかばん = these two bags

So the Japanese form stays この, but the English translation changes to sound natural.

It can mean either, depending on context.

買います is non-past polite form, and non-past in Japanese can express:

• a future action: will buy
• a habitual action: buy
• sometimes a general statement

In this sentence, because it is about choosing between two bags, the natural meaning is:

• I’ll buy the black one.

So it is future in sense, even though Japanese does not use a separate future tense form.

Yes, that is a very natural nuance.

Because of なら and ほう, the sentence often feels like a choice between two options:

• As for these two bags, I’d buy the black one.
• If it were these two bags, I’d buy the black one.

The comparison partner is not repeated after 黒いほう, because it is already understood from この二つのかばん.

It is most commonly used when comparing two things.

In this sentence, that fits perfectly because we have:

• この二つのかばん = these two bags

So 黒いほう clearly means the black one of the two.

While ほう can appear in other contexts too, learners should strongly associate this pattern with choosing between two options.

The sentence breaks down like this:

• この二つのかばんなら = if it’s these two bags / when it comes to these two bags
• 黒いほうを = the black one
• 買います = will buy

So the pattern is:

• [condition/topic + なら] [thing chosen + を] [verb]

This is a very useful structure for making choices:

• この二つの店なら、安いほうに行きます。

  • If it’s these two shops, I’ll go to the cheaper one.

• この二人なら、静かなほうが好きです。

  • If it’s these two people, I like the quieter one.