Thanks for this Vass - I agree.

In this line black has to sack a pawn for reasonable compensation (bishop's pair in an open position; some initiative) which is most probably not entirely sufficient.

Your views are much appreciated and very relevant: because this is the most critical line of this whole system.

Some good news - taking on c6 is played relatively seldom.

Thanks Vass - again you are hitting the hammer right on the nail here - this is a critical line of this variation. It has been played by Michael Tal, a great expert on the Modern Steinitz. 

It is discussed in Taylor's (quite good) book on the MS ("Slay the Spanish") who recommends 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O d6 6. Re1 Bd7 7. Bxc6!? Bxc6 8. d4 Be7 9. Nc3 exd4 10. Nxd4 Bd7 followed by 0-0, Re8, Qc8, b5 and Qb7 when he says black is OK. Black is very solid here. I think Taylor may have a point - although most players would say += due to white having more space, with careful defence by black he should be fine.

Another related line which is also very critical (maybe even more than yours!) and is due to Geller is 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O d6 6. c3 Bd7 7. d4 g6 8. Bc6:!? Bc6: 9. de5: Ne4: 10. Nbd2. Now white is slightly better after 10. ... Be7?! but Taylor gives 10. ... Nd2: or 10. ... Nc5 (with the idea Ne6) as possible improvements.   

Rather than the Russian variation, Taylor recommends the move order 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 d6 5.0-0 Bd7 6.d4! Nf6! which transposes to the variations above. I was hoping that with 5. ... Nf6 at least one of the two critical lines above could be avoided, but now it seems to me it doesn't make a difference.

If white doesn't go for the critical variations above but goes for the main line which is 1. e4 e5 2. Nf3 Nc6 3. Bb5 a6 4. Ba4 Nf6 5. O-O d6 6. c3 Bd7 7.d4 g6 8. Re1 b5 9. Bb3 Bg7, then I think we've arrived at a very complex position where black is perfectly all right. It's like a closed Ruy Lopez main line variation but with the bishop on g7 rather than e7, which I think is advantageous for black. I've done some computer analyses of this position and (according to teh silicon beast) contrary to normal middle game lore in quite a lot of variations black is doing well by playing ed4: cd4: so allowing white the "ideal" center, but then pressurising it.
 
PS: I've send you a personal message.

This stuff is interesting but quite risky for black - but he has a sound alternative in 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 d6 6.Re1 Bd7, with the idea 7.c3 g6 8.d4 b5 9.Bb3 Bg7, a line Keres used to play.

Thanks for this Vass and welcome to this post!

I wouldn't rate this variation as very passive. In particular the line you're discussing: 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 d6 6.Re1 b5!? 7.Bb3 Na5, is quite agressive - black goes after the bishop's pair and unbalances the position. In fact these lines are razor-sharp which doesn't count as passive for me - it's just the question if black is OK y/n, which is admittetly debatable. 

If white would have a long variation at his disposal which ultimately results in a draw is not a major worry for me either.

I would have to look at your interesting suggestions in detail to give a proper judgement. I wonder though if after 11.Qe2!? black can't go 11. ... d5!? to get a kind of Open Ruy on the board.   

Another razor-sharp variation and quite fun is 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 d6 6.Re1 b5!? 7.Bb3 Na5 8.d4 Bb7 9.Bg5 h6 10.Bh4!? Nb3: 11.ab3: g5 12.Bg3 Ne4: and now white should sac a piece with 13.Ne5:! (Spielmann) de5: 14.Be5: f6 15.Qh5+ Kd7! with an equal position.

The subtle point of 8. ... Bb7! over the old main line Nb3: 9.ab3: Bb7 is that in the latter line, black gets in trouble after 10.Bg5! h6 11.Bf6: Qf6: 12.Qd3 Be7 13.Nc3 c6 14.d5! and black can't play c5 due to 15.Nb5: ab5: 16.Qb5:+ and Qb7:. If black delays swapping the Bb3, this line doesn't work because the Bb7 is protected by the Na5.   

The Russian Defence (C79) is 1.e4 e5 2.Nf3 Nc6 3.Bb5 a6 4.Ba4 Nf6 5.0-0 d6!?. It is currently quite out of fashion, but is it bad? I don't think so. It leads to interesting and complicated positions. Some variations:

A]6.d4?! is not good after 6. ... b5 7.Bb3 Nd4: 8.Nd4: ed4: and after 9.Qd4:?? we have Noah's ark trap 9. ... c5 winning a piece because c4 is to follow.

B]After 6.Bc6:+ bc6: 7.d4 black is quite OK with 7. ... ed4: 8.Nd4: c5 9.Nf3(!) [after 9.Ne2?! Bb7 10.Ng3 g6! black is slightly better] Be7 followed by 0-0, Bb7 as in Spassky-Keres 1973.

C]After 6.Re1 black can go solid with 6. ... Bd7 or agressive with the interesting 6. ... b5!? 7.Bb3 Na5 8.d4 Bb7! with the idea 9.de5: Nb3: 10.ab3: Ne4: 11.ed6: Bd6: 12.Qd4 Qe7 and in this sharp position black is fine (13.Qg7:?! 0-0-0 or 13.Nc3 f5).

D]6.c3 is probably best but after 6. ... Bd7 7.d4 g6 8.Re1 b5 9.Bb3 Bg7 a complex position arises where I think black is quite OK.

All this makes me wonder - what's wrong with this variation and why is it out of fashion? What do you guys think?