best-kept secret

idiomatic

(idiomatic) Something interesting or important but not well-known.

Japanese Meaning

非常に知られていないが、実は興味深いまたは重要なもの

The little bakery on Elm Street has become the town's best-kept secret, drawing foodies from miles around.

エルム通りの小さなパン屋は町の隠れた名店となり、遠方からも美食家が訪れている。

Sense（1）

(idiomatic) Something interesting or important but not well-known.

Forget the Great Wall - Beijing's best-kept secret is its crazy taxi drivers.

best-kept secrets

（ plural ）