Opponent captures a piece there by putting you in check, and the opponent doesn't recognize check is it check?

Question

Opponent captures a piece there by putting you in check, and the opponent doesn't recognize check is it check?

Answer 1

doesn't matter what your opponent notcies or doesn't  if you are in check than it is ILEGAL to move withought getting out of Check. If your opponent doesn't notice and you move  while still in check than you are chesting. If neither of you notice than when you do notice you have to go back to the positiong that put you in check and replay it

Answer 2

irrelevant...

"A player may not make any move which places or leaves his king in check"

even if your opponent doesn't recognize it as check, you are not allowed to leave it as such.

Answer 3

yes

Answer 4

Yeah its still check. If you're playing in a tournament game and they don't realize its check, thats a great way to get them to lose a piece due the touch-move rule (worked a few times in my early years of playing chess)

Answer 5

Yes.

There are many chess players who believe the player has to look out for being placed in check, and don't say "check."