kono houchou wa yoku kireru node, ninjin o chiisaku kiru toki ni benri desu.

topic particle

Breakdown of kono houchou wa yoku kireru node, ninjin o chiisaku kiru toki ni benri desu.

• です: to be
• を: direct object particle
• に: time particle

Questions & Answers about kono houchou wa yoku kireru node, ninjin o chiisaku kiru toki ni benri desu.

Why is 切れる used here? Is it the potential form of 切る?

Yes—here 切れる is the same form as the potential of 切る, and with a tool like 包丁 it often means can cut well or simply is sharp / cuts well.

So:

• 切る = to cut
• 切れる = can cut / cuts well

In this sentence, この包丁はよく切れる does not mainly mean this knife is able to cut in the basic sense. A knife is obviously for cutting. Instead, it means the knife cuts efficiently or sharply.

So a natural interpretation is:

• This knife cuts well
• This knife is nice and sharp

One thing that can confuse learners is that 切れる can also be an independent intransitive verb in other contexts, but here the meaning is clearly cuts well.

What does よく mean here? Does it mean often or well?

Here, よく means well, not often.

That is a very common point of confusion because よく can mean both:

• often
• well

Examples:

• よく日本語を勉強します = I often study Japanese.
• よく見える = can see well
• よく切れる = cuts well

In this sentence, because it is describing the performance of a knife, well makes sense:

• この包丁はよく切れる = This knife cuts well.

If you tried to read it as often cuts, that would sound strange.