keep one's cards close to one's chest

English

The figurative sense is a self-evident extension from the literal sense.

(idiomatic, figurative) To avoid revealing one's thoughts, circumstances, or plans.
Synonyms: keep one's counsel, chest one's cards
- 1997, Sabine Rewald, “Balthus's Magic Mountain”, in The Burlington Magazine, volume 139, number 1134, page 626:
  Balthus has always kept his cards close to his chest. When I asked him if Summertime was a transcription of Poussin's Echo and Narcissus—a variant of his lost copy—he did not reply.
- 2002 December 25, Anil Netto, “Malaysia: Year of surprises and hardships”, in Asia Times, retrieved 25 Oct. 2008:
  Abdullah has not yet revealed his choice for the No 2 post when he takes over as prime minister, preferring to keep his cards close to his chest.
- 2023 June 28, Ben Jones, “Are we getting rid of our (still useful) rolling stock too early?”, in RAIL, number 986, page 29:
  However, the operator is keeping its cards close to its chest.
(card games, literal) To hold one's hand close to one's chest so that other players cannot see the cards.