Responding to Unusual Opening Moves

I wanted to started this thread for advice and analysis regarding responding (as Black) to unusual opening moves by White.

I'll start. What line(s) would be advantageous for Black when responing to, for example:

1.g4

1.b4

1.b3

1.f4

Others?

Currently the strongest line against 1.b3, in my opinion, is the rather strange 4..Bd6:

The Bd6 move looks ridiculous, but it has a very clever idea. In more classical variations where black grabs the center (3..d5 4.Bb5 Bd6) his center may come under attack from moves like f4. While these variations are good for black, Bd6 is somewhat more ambitious, it attempts to take the center while giving white no counterplay against it:

This is done by playing Bd6, 0-0, Re8 bringing the bishop back to f8 and playing d5, when black has the center and has deprived white of their fun in playing against it quickly. Moreover, if white captures on c6, blacks LSB gets freed easily and he has a good position.

Now, the two games I gave above do not show the plan of Re8 Bf8 and d5 unfortunatley, because white has tried to play against it, and black was given other options (such as ..Be5) which are also common.

In my own personal experience, I've found that when someone leaves the center completely open like that you should accept the gift and accupy it with a pawn as a general rule.  The reason is because it starts giving you central control, and gives you space which you can use to get your pieces developed and get activity.  And activity can be converted into both structural and materal advantages.

Ya, I agree. I would also add that If your opponent decides to play first move that doesent occupy the centre Thats exactly where I would develop my pieces. Centre control wins countless games :)

Nice. Anyone have anything for 1.g4? Some guy was swearing he kills everyone by starting with this (rolls eyes). I lookin in a book I have that talks about Black responding to unusual openings, and 1.g4 was not among them. Maybe this is not "unusual," but I don't know how to respond.

Against 1.b3, best is the main line of the diagram that follows, and is what I used to beat a 2447 player in Columbia, SC back in 2010.

Against 1.b4, my own opening of choice for White, the best line is the Exchange Variation with quick castling and Re8.  See the sideline below.

Regarding my research on your opening with 1.b4...

My understanding is Black can equalize in various ways. For example, 1...d5 2.Bb2 Bg4.

Even better for Black might be to play for advantage with the pawn exchange 1...e5 2.Bb2 Bxb4 3.Bxe5 Nf6. Black ends up two tempi ahead, which beats the slight profit White gained from the pawn exchange no problem. If three tempi equal a pawn, then two tempi are worth more than the modest difference in value between these pawns.

The important point to remember is not to play ...Nc6 until after ...O-O, ...d5, and ...c5. Black's ultimate aim is d5-d4.

Perhaps your success from 1.b4 is due, in part, to your opponents being unprepared, coupled with your ability to outplay them after the opening?