I still don't know how sound the 6...c6 variation in the Dutch Leningrad is. But it's obvious that it will be a more tempting repertoire choice if it's also playable against the Nh3 system. My preliminary investigations hint that it seems fully playable but that it takes some inventiveness and courage to keep the line's independent character:
1.d4 f5 2.g3
2.c4 Nf6 3.Nc3 can lead to the same lines.
2...Nf6 3.Bg2 g6 4.c4 Bg7 5.Nc3
This is roughly twice as popular as 5.Nf3. Yet the position arising after 5.Nf3 occurs almost as frequently as the one after 5.Nc3. The explanation of course is that there are many paths to the Nf3-set-up where the knight arrives earlier on f3.
5.Nh3 is a considerably rarer move but after 5...0–0 6.0–0 c6 7.Nc3 Na6 play will generally transpose to the main line after 8.Nf4. In addition White can try:
a) 8.d5 Qe8 9.Rb1 d6 10.b3 c5 11.Bb2 Rb8 12.Nb5 Bd7 13.a4 Ra8 14.Nf4 Qc8 15.h4 Nc7 16.Nc3 += Andonovski-Nikoloski, Struga 2002.
b) 8.b3 d6 9.Bb2 Nc7 10.Qc2 e5 11.dxe5 dxe5 12.Ba3 Re8 13.Rad1 +=
c) 8.Rb1 d6 9.b4 Nc7 10.e3 Bd7 11.a4 a6 12.Qb3 Kh8 13.Rd1 Qe8 14.b5 axb5 15.cxb5 Ne4 unclear Vorisek-Danner,
This is the characteristic move. But 6.Nf3 is almost equally popular.
Is it possible that this move can have independent value against the Nh3 systems too?
7.0–0 Na6 8.Nf4 is just an alternative move-order.
7...d6 immediately leads to positions normally arising from 6...d6.
8.0–0 Nc7 (Dia)
Black is determined to stay away from well-trodden
a) 9.e4 fxe4 10.Nxe4 Nxe4 11.Bxe4 d6 12.Bg2 e5 13.Ne2 Nc7 14.Be3 Bg4 =+ Kaminik-G.Danner,
b) 9.b3 d6 10.Ba3 Nc7 11.Rc1 g5 12.Nh3 Qg6 13.f4 g4 14.Nf2 h5 unclear
This is the point where White must decide: Should he play a neutral developing move which may prove irrelevant when Black at long last plays ...d6? Or should he play 9.d5 before Black has played ...d6 (when there is no genuine weakness to nail on e6)?
This is relatively noncommittal.
a) 9.b4 d6 10.Qb3 e5 11.c5+ d5 12.dxe5 Ng4 13.Bb2 Kh8 14.Nd3 Qe7 15.f4 Ne3 =+ Amura-Ad.Rodrigues,
b) 9.Qb3 d6 (9...Qe8!?) 10.d5 cxd5 11.cxd5 Nd7 12.Rd1 Nc5 13.Qc2 a5 14.Be3 N7a6 15.Bd4 and White had won the opening duel in Stimpel-Meier,
c) 9.d5 cxd5 10.cxd5 and now:
c1) 10...d6 11.Be3 Bd7 12.Rc1 g5 13.Nh3 h6 14.f4 g4 15.Nf2 += Moschell-Neubert,
c2) 10...e5 awaits practical tests, e.g. 11.dxe6 (11.d6!?) 11...dxe6 12.Qb3 Kh8 13.Rd1 Qe7 14.Nd3 e5 15.Be3 Rd8 16.Bc5 Qe8 with unclear play.
Can it be that ...Nc7 is more useful than Rb1? If nothing else the knight move is more relevant for Black's weaknesses in the e-file.
a) 9...d5 looks independent but I doubt it’s sufficient for full equality.
b) The untested 9...Qe8!? 10.d5 e5 is worth a try, e.g. 11.dxe6 dxe6 12.Qd6 Rf7 13.Nd3 Ng4 14.h3 Bf8 15.Qf4 e5 16.Qd2 Nf6 looks roughly even.
White is trying to steer play back to well mapped terrain.
10...Bd7 as well as 10...e5 11.dxe6 Nxe6 return to known
a) 11.c5!? should be tested.
b) 11.dxc6 bxc6 12.c5 d5 13.e3 e5 14.Nfe2 g5 15.b4 a6 16.Na4 Be6 17.Nb6 Rd8 =+ Arva-Albert, Goed 2004.
This risky pawn push fits well with Black's previous play but the timing can be discussed. Alternative tries are:
a) 11...Rf7 12.dxc6 bxc6 13.b5 Bd7 14.Qa4 cxb5 15.Qa5 Rc8 16.cxb5 Ne4 17.Nxe4 fxe4 18.Bxe4 Nxb5 unclear Zeller-Ennenbach, Schwaebisch Gmuend 1993.
b) 11...cxd5 12.Nfxd5 Ncxd5 13.cxd5 Bd7 14.Be3 Rc8 15.Bd4 Rc4 16.e3 Ng4 17.Bxg7 Kxg7 18.Qd2 += M. de Souza-Miguel, Pouso Alegre 1998.
c) 11...Bd7 and now:
c1) 12.Bb2 g5 13.Nd3 e5 14.dxe6 Bxe6 15.c5 d5 16.e3 Rd8 17.Ne2 Bc8 18.Be5+= Goy-R.Schmidt,
c2) 12.dxc6 bxc6 13.b5 Rc8 14.a4 Ng4 15.Qb3 Kh8 16.Bb2 g5 17.Nd3 Ne6 18.Nb4 Nd4 19.Qd1 c5 20.Na6 Qh5 (-/+) 21.h3 Ne5 22.Re1 f4 23.g4 (23.Ne4) 23...Bxg4 24.hxg4 Nxg4 25.Ne4 Qh2+ 26.Kf1 Ne3+ 27.fxe3 fxe3+ 0–1 Landenbergue-Klauser,
12...h6 13.Bb2 e5 14.dxe6 Bxe6 15.c5 d5 16.e3 Rd8 17.Ne2 a6 18.a4 Bc8 19.Nd4 += Biliskov-Zelic, Sibenik 2005.
13.cxd5 Qg6 14.Rb3 Bd7 15.a4 Ne4 16.Nxe4 fxe4 17.Nb2 Rac8 18.Re3 Bf5 19.h3?!
White's pieces are strangely placed and he doesn't have time for this preparatory move. The immediate 19.g4 was necessary, leading to a very messy position.
Now the pawn on d5 is doomed and Black takes over the centre.
20.Bxe4 Bxe4 21.Rxe4 Nxd5 22.Rg4 h6 23.b5 Nc3 24.Qd3 (Dia)
I like this strange move. It probably can only be found by calculation and is the kind of move I keep missing all the time.
Even stronger was 25...Rxc4 26.Nxc4 Rc8 with a winning position.
26.Rfxc1 Qxf2+ 27.Kh1 Rcd8 28.R4c2 d5
Black keeps a clear - perhaps winning advantage but his play is less exact in this phase. I assume both players were short of time by now.
29.Rg1 Qf7 30.Nd1 e5 31.e4 dxe4 32.Qxe4 Rd4 33.Qg2 Rxa4 34.Ne3 Qb3 35.Nd5 e4 36.Rd1 Rf7 0-1 Saulin-Sambuev, Moscow 2006. It seems likely White lost on time but objectively his position is hopeless.