How does b4 fix pawns in this endgame? Here, it is said that after 1.Re7 Rb8 2.Kd3 a6, white plays b4 to fix the enemy pawns. But I don't understand: how does it fix pawns? How is b3 any different? What does it mean to fix enemy pawns?
It definitely prevents Black from playing ...c5, at least temporarely. I wouldn't say Black pawns are &quot;fixed&quot; though. Anyway, isn't Re7 a much stronger move?