
Checkmate on Sheldon.
The Big Bang Theory Season 4, Episode 22

Checkmate would be irreversible."
Money Heist Season 1, Episode 8

...isn't that CHECKMATE
and I win?
The Big Bang Theory Season 5, Episode 18

I believe that is
flag to crotch four, CHECKMATE.
The Big Bang Theory Season 10, Episode 10

Checkmate.
The Big Bang Theory Season 12, Episode 17