It's a Funny Old Game.

Black is checkmated.


Yet the position is illegal.

It cannot be White's move with Black in check.
So what was White's last move?

So we agree the above postion is illegal.
However spin the board around.


And now it's legal!

It's a Funny Old Game.

yes, stupid rule that forbids white to promote to his own backrank....

Great! Couldn't get it at first. Till Mephisto made his post.