Three lights

In other words, a chess game that is won by the first player to fire their opponent three times. It seems like a game that could be played in a pub. What do chess experts think?

yes, this variant is also played on very popular chess servers...a very welcome suggestion ;)

Okay. Now about the rules. Everything else is as usual, but whoever gives three lights to the other first wins. Hm. I think that then the number of lights given should be displayed somewhere (maybe next to the player's name?). BTW - The shepherd still counts in this game. That is - checkmate and sin still end the game if three lights have not been given yet?

Yes, checkmate and sin end the game like in regular chess. And the number of lights given should definitely be displayed somewhere. Otherwise, it would be hard for some to follow.