user10221: [StartPly "10"]

[fen ""]
1.e4 c5 2.Nf3 Nc6 3. d4 cxd4 4.Nxd4 e5 5.Nb5 Nf6 *

5...Nf6 looks like a good move for black, however I failed to find analysis about this variation. Am I overseeing something, why would black not want to play this move? What is the best next move for white?
6.N1c3 does not seem good because of 6...Qa5 (6.Bg5 for the same reason), and 6.Nd2 would make white to lose the ability to pressure Nd6+ and would close the bishop at c1.

user7297: White's best move seems to be 6. N1c3, when 6... d6 transposes into the Sveshnikov.
After 6... Qa5, White just replies 7. Bd2, threatening Nd5 and Nc7. Black has nothing better than 7... Qd8 when White enjoys a huge advantage in development.

10221: <pre><code>[StartPly "10"]

[fen ""]
1.e4 c5 2.Nf3 Nc6 3. d4 cxd4 4.Nxd4 e5 5.Nb5 Nf6 *
</code></pre>

<p>5...Nf6 looks like a good move for black, however I failed to find analysis about this variation. Am I overseeing something, why would black not want to play this move? What is the best next move for white?</p>

<p>6.N1c3 does not seem good because of 6...Qa5 (6.Bg5 for the same reason), and 6.Nd2 would make white to lose the ability to pressure Nd6+ and would close the bishop at c1.</p>
 7297: <p>White's best move seems to be 6. N1c3, when 6... d6 transposes into the <a href="https://en.wikipedia.org/wiki/Evgeny_Sveshnikov#The_theoretician" rel="nofollow">Sveshnikov</a>.</p>

<p>After 6... Qa5, White just replies 7. Bd2, threatening Nd5 and Nc7. Black has nothing better than 7... Qd8 when White enjoys a huge advantage in development.</p>
