It's G1, isn't it? And since that makes a mirrorable (is it a correct word?) position; I'm almost sure that it leads to a draw.
I wonder if that tutorial you were speaking about is no longer on the internet. I remember reading a very long tut. about 1-2 months ago. Was that it?
I suggest a new way of pointing mistakes alike (but not the same) in chess:
let "??" mean that from a winning position player made a move which enables his opponent to win. ("two grades down")
let "?" mean, that from a winning position player made a move, which enables his opponent reach the draw, or from a draw position - to a loss. ("one grade down")
let "!" mean a move that leads to a draw, when your opponent made a "?" mistake. ("one grade up")
let "!!" mean a move that leads to a win, when your opponent made a "??" mistake. ("two grades up")
Task #9
1. A1?? - A2?? (that's back to normal - reds can win again, because yellows lost their chance)
2. D1 - D2
3. D3 - C1
4. C2 - C3
5. D4? - D5!
6. C4 - G1
7. G2 - G3
Where red can reach the draw now? I think the difficulty of it is medium.