The Evans Gambit EXPLAINED

The Evans Gambit is a chess opening characterised by the moves:

1. e4 e5

2. Nf3 Nc6

3. Bc4 Bc5

4. b4

The Evans Gambit is an aggressive line of the Giuoco Piano. White offers a pawn to divert the black bishop on c5. If Black accepts, White can follow up with c3 and d4, ripping open the centre, while also opening diagonals to play Ba3 or Qb3 at some point, preventing Black from castling kingside and threatening the f7-pawn respectively.

If Black declines, the b4-pawn stakes out space on the queenside, and White can follow up with a4 later in the game, potentially gaining a tempo by threatening to trap Black's dark-square bishop.

According to Reuben Fine, the Evans Gambit poses a challenge for Black since the usual defences (play ...d6 and/or give back the gambit pawn) are more difficult to pull off than with other gambits. (Fine was once beaten by this gambit in a friendly game against Bobby Fischer, in just 17 moves.)

The rest of the game will leave black struggling to hang on.

It's my favourite opening

5...Ba5 is much better than 5...Bc5
5...Bc5 allows d4 to win another tempo, 5...Ba5 saves that tempo

I have seen lines where b4 is met with Bb6, a4, a6 a5 Ba7 white gaining space on the queenside and black maintaining the diagonal pressure on f2. Similar to a quiet game.

#4
Here is a famous game with the gambit declined
https://www.chessgames.com/perl/chessgame?gid=1070779 

in the last example nearly every move is a blunder. Qh3 hangs a Queen. g6 hangs a knight, which for some reason white doesn't take. those are the biggest ones, but there are more.

SImon WIlliams has a pretty good Lesson on the Evans Gambit here:
https://www.chess.com/lessons/spicy-openings-the-evans-gambit

I learnt it from him

It's an aggressive, sharp and open line that will keep both players on their toes (not literally) XD