Exercice : the open file

In this position the black has a better position, but to stay in advantage he must find the better way to play. We must consider the importance of the "a" open file.

In this position , the black can't win immediatly, but we must find a plan to have a better position.

Maybe ...Qa8 ?

1...Qa8 2. Qxa8 Bxa8 3. Ne2 Bxd5 4. exd5 Nxd5, black wins a pawn

1...Qa8 2. Qxa8 Bxa8 3. Bxa8 Rxa8, black gets the a-file

1...Qa8 2. Bxc6 Qxc6, the e4 pawn is under attack and black is ready for ...Ra8

Does it make sense? (at least a bit :-) )

Ba8 looks better to try and maintain the battle on the a file.

I would also note that the position looks unlikely in an actual game

I think both the moves are ok, with Ba8 or Qa8 we took the file, with a good position!