My attempt
Emojis, but naturally SPOILERS on the sequence length
Josekle #1
too few moves
too many moves
too few moves
too many moves
too few moves
correct!
I got a bit confused on the sequence in the middle, but it was very fun 
I think maybe an undo button to clean up the tree a little would be handy. I found myself misclicking a lot on mobile, so it might be handy not to have the misclicks hanging around.
Not a big deal and already a great implementation!
Edit: one initial confusion I had was that yellow meant “there’s a stone here at some point” but that stone could be either color.
So actually I just ended up ignoring the yellow hints altogether because it was harder to think of how the sequence ends up with a stone there but it could be either colour.
That might change in day 2