Is it bad etiquette to not say "check?"

I loudly yell ‘CHECK!!!’ at my phone when I’m playing in public. Just a habit.

Soon enough AI will respond to that in ways you've never imagined

eh, it can be good and bad. I don't usually say check bcs my opponents are high rated enough to know that it is check.

Jgh

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Yrt

I do not think that I have ever said "check" during a game. When absolute beginners start playing casual it might be useful for them to alert each other that they are in check. However, a player that has any kind of training should instantly know that they are in check. I did not learn to play until I was 11 year old, so I never got to play against against inexperienced players.

The only time I might of said "check" would have been when promoting a pawn during a blitz game or when adding an extra piece on the board in a chess variant such as crazyhouse.

Another time that you might want to announce check is if you want to emphasise that you are using repetitive check to draw the game.

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In lightning chess you never announce check, as you are allowed to take your opponent's king to win the game.

You aren't supposed to talk while playing chess so you shouldn't say check.