1. d4 d5 2. c4 e6 3. Nc3 Bb4 4. cxd5 exd5 5. Bf4 c6 6. e3 Ne7 7. Qb3 Bd6 8. Bxd6 
Qxd6 9. Bd3 b6 10. Nf3 Ba6 11. Bxa6 Nxa6
ICCF
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ICCF Game
1.      d4 d5 2.c4 e6 3.Nc3 Bb4 4.cxd5 exd5 5.Bf4 c6 6.e3 Ne7 7.Qb3 Bd6 8.Bxd6 Qxd6 9.Bd3 b6 10.Nf3 O-O 11.O-O Ba6 12.Ne1 Bxd3 13.Nxd3 Nd7 14.h3 Rfc8 15.Rfc1 h6 ...
Home > Tables and results > Max Zavanelli Memorial Tournament Section C > Game
CCM Gareth Yeo (2425) IM Pierre LeBled (2391) 1/2-1/2
1.d4 d5 2.c4 e6 3.Nc3 Bb4 4.cxd5 exd5 5.Bf4 c6 6.e3 Ne7 7.Qb3 Bd6 8.Bxd6 Qxd6 9.Bd3 b6 10.Nf3
O-O 11.O-O Ba6 12.Ne1 Bxd3 13.Nxd3 Nd7 14.h3 Rfc8 15.Rfc1 h6 16.Rc2 a5 17.Rac1 Rab8 18.Na4 Nf6 19.Qc3 Ne4 20.Qe1 g6 21.Nc3 Rb7 22.Nf4 Rbc7 23.Nfe2 Nf6 1/2-1/2
The start date was 8/31/2018.
Latest results from 9/7/2020 are displayed in red.

Justinhorton - I don't believe you've missed anything. When I check the position after 11...Nxa6 with Stockfish, Dragon, and Lc0, they all give your line ending with 16.Nd2 with an edge for White, although Lc0 doesn't rate the advantage as quite highly as the other two engines.

If "Somebody else must have spotted this by now", I haven't been able to find an explicit statement to that effect. There are some comments on the chessgames.com link you provided, but nothing about the possibility of 12.Nb5. ChessBase reported on the Navara-Hou match, but their account of Game 2 also didn't mention 12.Nb5. The ChessBase report said that Navara was playing positionally in the match to avoid Hou Yifan's tactical strength. Thus he may not have been looking for a tactic himself.

I wasn't able to find the position after 9.Bd3 in any of my books, and it didn't turn up in Chesspub's Nimzo-Indian or 1.d4 d5 sections, in ChessBase's Opening Encyclopaedia, or in any English-language Chessable courses. (It may appear in German and Spanish courses to which I don't have access).

The lack of attention to 12.Nb5 may arise from the relative rarity of the preceding position. A search of the Mega Database of the position after 9.Bd3 yields only nine examples, including Navara-Hou. In some of these games, Black goes for ...Nd7 on move 9 or after castling, so the ...Ba6 plan never comes up. The only annotated game among the nine is Sevian-Swiercz, St Louis Spring-A 2022, which has annotations by GM Spyridon Kapnisis, apparently from ChessBase Magazine 207 Extra. This game deviates from Navara-Hou at move 10, when Sevian played 10.Rc1. The game continued with Black going for the same bishop exchange as seen in Navara-Hou: 10...b6 11.Ba6 Nxa6. Now Kapnisis makes no comment about 12.Nb5, possibly because the move isn't as strong as it was in Navara-Hou. Stockfish indicates that Black can reply 12...Qd7 when White only has a very slight edge. Note that 12...Qd7 isn't good in the position arising from 10.Nf3 because White can reply 13.Ne5, bringing the knight to a good square with tempo by hitting the black queen. Stockfish regards this as clearly +-. As an aside, Swiercz has written a book on the Ragozin, but the position of interest isn't covered since he begins with 1...Nf6.  That was also the case when I looked for the position in other books I have.

A search of the UltraCorr database for the position after 9.Bd3 finds three correspondence games from the 2018-2021 period. In all of them, after 9...b6 10.Nf3, Black castled before playing ...Ba6. These games suggest that the Black players were aware of the 12.Nb5 tactic and took measures to avoid it. I don't know if engine assistance was allowed in these games, or if the players had 12.Nb5 in their files through having analyzed the position at some previous point, but it does seem as though "Somebody else must have spotted this". However, announcing this publicly seems to have been a different matter.

After 1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. Nc3 Bb4!? 5. Bg5 dxc4 6. e4 c5 7. Bxc4 cxd4 8. Nxd4, Pert champions  8...Qa5!? instead of the main line 8...Bxc3ch. The two moves may or may not transpose. Panczyk and Ilczuk also cover both moves. I'm pretty much sold on the idea that 8...Qa5 is the easier and more solid continuation.

FreeRepublic wrote on 10/22/21 at 01:27:33:


I will quickly add to this, explaining a further key point of Bb4+ then back, to Bd6 or Be7. 
Not just displacing the bishop, which gets in the way on d2, and is better on c1 ('Shall I go to f4, or b2/a3 - I will wait and decide later' - like waiting on the weather report before deciding your attire for the day, perhaps). It also takes the d2 square from the f3-knight, which goes there in one line to support a quick e4 (the c3 knight going naturally to c3). Bologan gives this, iirc, and I am sure it has come up hereabouts too.

Cornette's main recommendation is also 5...c6.  He notes that Pert came to the same conclusion in "Playing the Ragozin".  The main line in Cornette's analysis continues 6.e3 Ne7 7.Bd3 Bf5 8.Nge2 Bxd3 9.Qxd3 Ng6 10.Bg3 Nd7 arriving at equality by move 13.

Cornette also provides brief analysis of 5...Ne7 and 5...Nf6, mostly to show that they're inferior to 5...c6.  He cites Kornev's book in giving 6.Qa4+ as a good reply to 5...Ne7.

ErictheRed wrote on 07/24/17 at 19:50:17:


I've just started looking at it:
1. d4 Nf6 2. c4 e6 3. Nf3 d5 4. g3 Bb4+ 5. Bd2 Bd6
 
ChessPub calls this the Ukrainian variation. CP is positive in the introduction to the line and I have not gone further.

There are several ways for black to play 4...Bb4ch, or 4...dxc 5Bg2 Bb4ch. The distinctive thing about the Ukranian/Pert variation is the retreat ...Bd6. Pert often turns this into a Stonewall Dutch type of position.

For starters, the Dutch formation remains an option. Yes, Pert often goes that way, but it is not mandatory. Another thing is ...Bd6 in the Stonewall Dutch (SD) became fashionable a few years ago. This is not a novel piece placement.

Obviously black lost a tempo with Bb4ch-Bd6. That would be a concern if the white bishop were well placed on d2. However, I'm not aware that white ever chooses to play Bd2 in the SD. Instead, white commonly plays b3 and either Bb2 or Ba6. Attempting that here will cost three tempos (Bd2-Bc1-Bb2), putting white a tempo behind normal SD lines.

A major line in the SD has black playing ...Bd6 and white answering Bf4. That could happen here too, with players on tempo. The only thing is that black may not have committed to the Dutch (...Ne4 ...f5) structure yet. I'm not sure.

Pert also covers Bg5 lines on tempo. These are somewhat rare in the SD, but not unheard of.

The Ukrainian/Pert variation has good win/loss statistics, so that may be a good macro indicator. It might lead to an improved Stonewall Dutch. That could be very important. My biggest problem is that I don't play the Stonewall Dutch!

fjd wrote on 11/24/16 at 23:53:59:


I would want to avoid playing the black side in that famous game. I've spent a little time looking at Pert's analysis of 1. d4 Nf6 2. c4 e6 3. Nc3 Bb4. He provides some fascinating stuff that one might encounter in actual play.

As far as I can tell, the greatest concern black has occurs after:

1. d4 Nf6 2. c4 e6 3. Nc3 Bb4 4. a3 Bxc3+ 5. bxc3 d5 6. cd5 ed5 7. e3 Bf5 8. f3 O-O 9. Ne2

Pert looks at 9...c5 and 9...Re8. Here 9...Nc6 has done pretty well in high rated games and is preferred by my engine.

We've avoided Botvinnik-Capablanca. I'm too confused at the moment to tell you when.

As to the position after 9.Ne2, I suggest looking at it with one's own eyes. It's just as dangerous as it looks. At the moment, it seems to me that if one can talk oneself into liking this position as black, the entire concept (1c4 e6 2Nc3 d5 3d4 Bb4) becomes viable.