Is this a sensible plan in the Italian game?

In the Italian Game is it sensible for white to eventually place their bishop on the a4 square? In other words is going Ba4 a good idea for white?

The bishop wants to focus on the f7 weakness, so it tries to stay on the a2-g8 diagonal.

How are you getting to a4? It would take a couple of moves to get there in the Italian.

In the Italian I don't see the Bishop going to a4...

In the Spanish (or the Ruy Lopez, whichever you call it) the Bishop going to a4 is quite common as after 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 is often played.

In the Italian game the dark squared Bishop (the other Bishop) often goes to a3, at least if you play the Evans Gambit.

The bishop can go from b3 to a4.

Yes, it will take a couple moves. By that time black should’ve castled, and there wouldn’t be much point for Ba4. The only reason I see for Ba4 is to pin the knight if black hasn’t castled, but I don’t think it will last. Staying on the a2-g8 diagonal exerts pressure which could last a while.

What about using it to maintain the possibility of exchanging the bishop for the knight while making it easier to switch between targeting two different diagonals, such as the a4-e8 diagonal and the a2-g8 diagonal?

If you wanted to exchange, then it might’ve been better to play the Ruy Lopez instead. When you’re playing, you want to find the optimal position for your pieces, so either go with the Italian or Ruy Lopez in this case. Trying to switch between the two seems like wasting moves.

Introduction to The Italian Game & Evans Gambit...

https://www.chess.com/blog/RussBell/introduction-to-the-italian-game

https://www.chess.com/blog/RussBell

In my last daily game I put the bishop on a4

In the giuoco piano I want a Queen on b3 so having a bishop on a4 would be asking for trouble

Actually, with the exception of d6, everything is book move. Yes, I can see the bishop going to a4 in this case, but not through b3. 

What if a threat can be placed on different diagonals in succession in order to create a combination or extra threats that black has to deal with in order to create tactical threats?

Also, what if it's not the Ruy Lopez that we are trying to transpose to, what if we are aiming for a transposition to the double Spanish four knights?

Why would going Ba4 in the giuoco piano be asking for trouble?

If you play Qb3 like me it might run into c6/a6 then b5 and the bishop would have no where to go.

In other words if white was to go both Qb3 and Ba4 the light squared bishop would become trapped?

Yes, you should just play the Spanish if you're interested in Ba4

In order to avoid trapping the bishop, simply don't play Qb3.

Mhm

Sure if you want to completely ignore the nice diagonal that runs straight through the centre of the board in the open games

In most lines, putting the bishop on a4 after putting it on c4 is simply a waste of time. As was previously mentioned, if you wanted it there, you ought to have played the Ruy Lopez.

that's great!