Here is again the proof that 1 e4 e5 2 Ba6? loses by force for white.
If white plays differently, then white loses quicker.
A win is easier to prove than a draw.
Even without such constructive proof it is and was known that 1 e4 e5 2 Ba6? loses: a full piece down with no compensation of any kind.
I gave above proof that 1 g4? loses by force for white, which is more surprising a result.
@6584
"for all practical purposes it's already been solved"
++ For all practical purpose chess is ultra-weakly solved: the game-theoretic value of the initial position is a draw.
We also have > 1000 perfect games with optimal play from both sides: ICCF WC Finals draws.
However chess is not yet weakly solved.
We know chess is a draw, but we do not yet know exactly how.
How to draw against 1 e4, 1 d4, 1 c4, 1 Nf3?