@6843
Shorter:
@6845
I think it is shortest. I have been looking at ways to capture Ra8 at its initial square and thus saving the move 10...Rb8, but I could not find a way.
1 move shorter without bQd3. Is it possible to shorten more?
I can shorten your proof game by 1 half-move:
Another way to make it legal
That's a trickier way. I'm sure someone can shorten this.