ただ一ひとつ

noun which may take the genitive case particle 'no', noun, adverb

sole; only; just one

Emphasizes that there is exactly one of something, often used with a sense of uniqueness or preciousness. Can function as a noun, adjectival modifier with の, or adverbially.

• これがただ一ひとつのチャンスだ。

  This is the sole chance.

• 彼かの女じょはただ一ひとつの願ねがいをかなえた。

  She fulfilled her only wish.

• ただ一ひとつだけ覚おぼえておいてほしい。

  I want you to remember just one thing.