Tactics with mobile central pawns
Tactical devices that carry out the central pawns' advance
To carry out your plans, use every tactical possibility you can find. This always holds, including in positions with mobile central pawns.
Some positions look, at first glance, like the central pawns can't advance at all. Look closer, though: a tactical device may still make that advance possible:
The e3–e4 advance in the Queen's Pawn Opening
This pawn structure deserves attention. It arises in the Queen's Pawn Opening (and, with colors reversed, in the Slav Defense):
The pieces can stand in various ways here (for example, White's bishop may go to c1, f4, or g5 in the opening stage). In positions with this structure, White often pushes the e3-e4 pawn, backed up by the pieces.
Once White carries out this advance, White gets a choice: trade on e4xd5, push on to e4-e5, or keep the tension in the center. Having a choice is already an achievement.
Still, White's advance to e4 sometimes runs into resistance, since Black can play c5xd4 and d5xe4 and give White an isolated pawn, which can become a weakness. (The isolated pawn's problems are covered in a dedicated section.)
Black's move c5-c4 makes the e3-e4 advance considerably easier and stronger for White. Thanks to the secure pawn on d4, White then feels much freer in the center. If instead Black tries to seize space on the queenside with b7-b5-b4, that brings less than in the positions covered in "A majority in the center or on a flank?", since there the flank had a pawn majority, which made it easier to create a passed pawn.