In the eighth edition of a popular manual by Jean Dufresne and Mieses (either Samuel or Jacques, I'm not sure which), the following line of play is given:
1. d4 d5 2. c4 e6 3. Nc3 c5 4. Nf3 cxd4 5. Nxd4 e5 6. Ndb5 d4 7. Nd5 Na6 8. Qa4 Bd7 9. e3 Ne7
leading to the following position:
In this situation, the author's comment is, "Black has the superior position." Keep this comment in mind.
Do you see what the analysts overlooked after Black's 9th move, Ne7?