As the old poem says:
For want of a nail the shoe was lost.
For want of a shoe the horse was lost.
For want of a horse the rider was lost.
For want of the rider the message was lost.
For want of a message the battle was lost.
For want of a battle the kingdom was lost.
And all for the want of a horseshoe nail.
Exactly the same principle applies in chess. ...
I'm not at all disagreeing with the existing answers - both sound. Indeed every pawn is a potential queen. However, one aspect of the question remaining is: why struggle for a pawn as opposed to a more decisive plan?
In the games that you are watching, if they are between capable and well-matched players, very often the game will be quite well balanced with ...
Another point which has not been raised by the excellent answers above is that pawns are easy to block. A pawn can be blocked by just one piece in front of it, and it cannot take the piece which blocks it. Contrast this with any other piece, which can take a piece which blocks its movement (barring other circumstances such as a pin).
This property means that ...
This is a bit trivial as an answer, but too long as a comment. You claim that you can develop "as good as White" but that is simply not true. White begins by interposing the Bishop 4.Be2. You play 4..Bg4. It is now a mistake to play 5.Nf3 because 5..Bxf3 spoils whites Pawns and makes his King insecure. But 5.d4! also gains a development tempo, and forces ...
Avoid queen mating on g2 is easy:
f3, Qg3, Qh3+ are decent options
Re4, Kf1 also prevent immediate mate but are not good
Winning this position is objectively speaking impossible. Black is up a piece and white does not have sufficient compensation for it. Most players would resign if playing somebody of 1800 strength or even less.
If black is a beginner and/...
Preceding answers and comments make many good points.
Why struggle for a single pawn?
The simple answer is: Chess games are mostly won by material advantage!
Generally being up a single pawn in an otherwise safe position is a clear advantage, often a winning advantage.
In such a situation a GM analyst might say: And the rest is technique!
Of course there are ...
The answer by @Brian Towers is both beautiful and true, but not always true. It is perhaps true if you think of every pawn as a potential queen. However, in endings, especially in Rook endings, the textbooks will tell you not to be drawn into passive defence but to keep your pieces active, and counterattack. That being said, you may not have the choice. ...
The 3. .. Qe5+ is not a great continuation for black. Because:
It does not threaten anything really. White can block with developing (!) a bishop: 4. Be2.
It places blacks Queen in the center very early in the game where it will be a target of the attack for many whites pawns and pieces. Square e5 is far from a permanent position for the black queen, and ...
But why it's a bad move?
You are moving your queen to a square where it is going to be attacked again soon and then you will have to move the queen for a third time. Meanwhile white is developing fast and you have no pieces developed.
You should think of pawns not as individual units but as a group acting as one unit. If one pawn is one "point" then the entire pawn formation is 8 "points". This actually makes pawns one of the most powerful units in the game. The pawns are your front line and do an excellent job of defending each other in diagonal lines. If your ...
Qe5+ is not a blunder or a mistake but it is definitely inaccurate play. Qa5 (most popular line) keeps a check on 2 central squares as well as Qd8.
Defending with bishop
Also in the second line you mentioned (Bc2) after Bg4, white has an excellent move d5! Now white has a tempo in development, space as well as development whereas black is trying to ...
Another possibility might be the Old Indian where Black plays d6, Nf6, c6 and aims for an early e5. You can also play like this against 1. c4. I think Nigel Davis did a Chessbase DVD on this, called "A busy person’s opening system". But I don't know it and I don't want to advertise it.
Although this might be "sound" more or less, I can't recommend such an ...