Ruy Lopez: Morphy Defense, Modern Steinitz Defense: what should Black play?

b5! — Excellent Choice!

✅ One of 4 top moves — you found a winning strategy!

Why this move is excellent: By playing b5, you immediately challenge the a4 and force it to a less active diagonal. This gain of space on the queenside prepares your development while neutralizing the pin on your c6.

Multiple Valid Strategies

This position is rich with options! You chose the most popular human response, but there were three other ways to maintain the balance:

Different paths, same destination: While b5 is the most direct and energetic approach, moves like Nf6 or Be7 focus on completing development first. All four moves lead to an equal game, showing that whether you prefer immediate expansion or patient setup, your intuition was spot on!

Your Continuation

After b5: Bb3 Nf6 c3 Be7 d4

What Made This Move Good

You correctly saw: The a4 was the most annoying piece in White's camp. By kicking it to b3, you've improved your coordination and paved the way for a smooth middlegame.

📚 Takeaway: In positions with multiple good moves, trust your style—whether you choose the aggressive expansion of b5 or the solid development of Be7, both are objectively excellent!