っけ— What Was It Again?

• あの人の名前、何だっけ？

  Ano hito no namae, nan dakke?

  What was that person's name again?

  Noun 何 + だっけ asks to recall a forgotten name in casual speech.

• 明日って休みだったっけ？

  Ashita tte yasumi datta kke?

  Was tomorrow a day off again?

  だった + っけ confirms a half-remembered fact about tomorrow.

• この鍵、どこに置いたっけ？

  Kono kagi, doko ni oita kke?

  Where did I put this key again?

  Verb た-form 置いた + っけ voices trying to recall one's own past action.

• ・Strictly casual — do not use in formal or polite writing.
• ・Often used talking to oneself, or checking shared memory with a friend.
• ・Nouns/な-adjectives usually take だっけ or だったっけ.

Commonly confused with

The JLPT rarely asks whether you recognise a pattern — it asks which of several similar patterns fits. These are the ones っけ is tested against.

• ～一方だ — Heading Ever Further In One Direction
• ～がちだ — Prone To It
• ～からいうと／からいえば — Speaking In Terms Of
• ～からして — Even Just From
• ～かわりに — Instead Of / In Exchange
• ～きり — Only / And Never Since
• だらけ — Covered All Over
• ～っぱなし — Left As It Is