The unintentional mates happen to me all the time. But I am that busy playing, I forget which ones they were, They are almost always when I am in bad time trouble.
Next time it happens you are more than welcome to share them here my friend. 
Royal forked my opponent and when I captured the queen I checkmated my opponent
I'm beginning to feel that almost none of my mates are intentional. Not only did I fail to notice the mate until it happened, I missed the mate-in-18(!!) a move or two earlier, which the analysis found afterwards. How could I have failed to spot it???
We weaker players have a lot of these unintentional mates,
I have so many that I would spend a lot more time reporting mine here,
But I do like this entertaining thread.
We weaker players have a lot on these unintentional mates,
I have so many that I would spend a lot more time reporting mine here,
But I do like this entertaining thread.
Under time pressure even the strongest of us might lose our senses as to see the bigger picture. Father-time breathing down one's neck is another ball-game.
I have a couple games like that but I can't find the exact game I thought of when I saw this
You could have ubintentionally played Rb8#
As I said before... Father time... 😮💨🗣️😱
https://www.chess.com/analysis/game/live/139321261589?tab=review&move=9
has to be unintentional as the coach more or less said so by telling me I was only going to win a knight, whereas it was a forced mate in 2.
The unintentional mates happen to me all the time. But I am that busy playing, I forget which ones they were, They are almost always when I am in bad time trouble.