Evan's Gambit

 I think there are 2 ways to get a development advantage.

One way is to move a new piece every move.

The other way is almost the same but in reverse that being make your opponent move the same piece twice.

I think the Evan's Gambit is trying to get a development advantage by the second technique.

Evans Gambit is trying to improve this major line of Giuoco Piano :

These variations were given (already!) by the italian theorician Greco in about 1615!

But of course, he didnt consider the black's best replies.

Then, black found ways to obtain a good game (i gave some lines), and it was up to white to find improvment.

At 19h century, white found this famous Evans gambit, which is just a try to improve this way to play :

Almost the same position than Giuco Piano, where white is a tempo up, but pawn down...

Is it worth a pawn? The big question...

So white ideas are :

- get a strong centre e4-d4

- gain some time attacking the black bishop

- like many e4-e5 position, white can launch attack on f7, and here Bc4-Qb3 is an idea.

This is just the beginning of the story but Evans gambit is very interesting and is a very good weapon at all levels.

The idea is to create an imbalance, white gets a dynamic advantage; rapid piece development, active pieces, and control of the center VS blacks static advantage; an extra pawn. White will try to use his dynamic advantage to attack black before he's ready, and black will try to quell the attack and make it to an endgame where his advantage (the extra pawn) will be useful. I hope this answers your question.

Seems kind of risky to me.

 Only if "risky" means "beautiful."