sankatouroku wa muryou nanoni, naiyou wa totemo kuwashii.

topic particle

Breakdown of sankatouroku wa muryou nanoni, naiyou wa totemo kuwashii.

• とても: very
• 参加登録さんかとうろく: registration
• 無料むりょう: free (no charge)

Questions & Answers about sankatouroku wa muryou nanoni, naiyou wa totemo kuwashii.

What does なのに express here?

It means “even though/despite,” with a nuance of surprise or contradiction. The clause before なのに sets an expectation; the clause after it states something that goes against that expectation. Here: “Even though registration is free, the content is very detailed (surprisingly).”

Why is it なのに after 無料 and not just のに or だのに?

Because のに attaches to a plain-form clause. With nouns and na‑adjectives, you use な before のに: noun/na‑adj + なのに.

• Noun/na‑adj: 無料なのに
• i‑adj: 高いのに
• Verb: あるのに Using だのに after a noun/na‑adj is not standard; stick with なのに.

What part of speech is 無料, and how do I use it?

無料 is a noun that behaves like a na‑adjective.

• Predicate: 登録は無料だ／です (Registration is free.)
• Attributive: 無料の登録 (free registration)
• Adverbial/means: 無料で登録する (register for free) In the target sentence it’s followed by なのに, so you need the な: 無料なのに.

Why are there two は’s?

They mark two contrastive topics:

• 参加登録は (as for registration) … 無料
• 内容は (as for the content) … とても詳しい This “Aは…, Bは…” structure highlights a contrast: free registration vs. very detailed content.