FreeRepublic wrote on 06/15/21 at 14:18:43:

The position reached after 1. d4 d5 2. c4 e6 3. Nc3 Nf6 4. cd5 ed5 5. Bg5 c6 6. e3 Be7 7. Bd3 Nbd7 8. Qc2 h6 9. Bh4 Nh5 10. Be7 Qe7 was first reached in 1933, but there is little evidence that it, or the game Donner-Tröger of 1958, had great influence. This line began to take-off (in games played) around 2014 but has had a real surge since the publication of the Ntirlis book.

The evidence of influence is there, it is just negative evidence: It had been tried, but did not become popular. The question is why not? This requires detective work. Now the really interesting question is whether Ntirlis has managed to improve on the earlier theory, or simply ignored it. This requires further detective work. That it experienced a surge after the Ntirlis book is totally understandable, expected even. As to whether this popularity will remain, only time will tell. This final point is related to the previous detective work, or lack of it.

*Caveat*: I don't have Ntirlis's book.

I don't have ECO D 3rd edition. In the 1st and 2nd editions it is D36 after

**1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.cxd5 exd5 5.Bg5 c6 6.Qc2 Be7 7.e3 Nbd7 8.Bd3** and now 1st edition line 6 note 23, 2nd edition line 4 note 15.

Both give Uhlmann - Müller, DDR (ch) 1974 (sic) as +/-, see Informator 19/505. The 1st edition (but not the 2nd) gives Gligoric - Estimo, Manila 1968 as +/-. In both these games, the stronger player won. The 1st edition also quotes a game Taimanov - Arhangelski, SSSR 1962, deviating from Gligoric - Estimo with 11...Nf8 and reaching +=. We can look at this "theory" in different ways. (a) The weaker players ignorantly played an inferior line and were thematically punished. (b) The weaker players played a good line; because they lost theory unjustly rejected the line. (c) Some intermediate conclusion is correct.

[Event "DDR-ch 24th"]

[Site "Stralsund"]

[Date "1975.??.??"]

[Round "15"]

[White "Uhlmann, Wolfgang"]

[Black "Mueller, Klaus Uwe"]

[Result "1-0"]

[ECO "D53"]

[EventDate "1975.02.02"]

[PlyCount "59"]

[Source "ChessBase"]

[SourceDate "1999.11.16"]

[WhiteTeamCountry "FRA"]

[BlackTeamCountry "GER"]

1.c4 e6 2.Nc3 d5 3.d4 Nf6 4.cxd5 exd5 5.Bg5 Be7 6.e3 c6 7.Bd3 Nbd7 8.Qc2

h6 9.Bf4 a6 10.Nf3 O-O 11.g4 c5 12.g5 hxg5 13.Bxg5 cxd4 14.exd4 Ng4 15.h4

Re8 16.O-O-O Ndf6 17.Ne5 Be6 18.Rdg1 Rc8 19.Bxf6 Nxf6 20.h5 Ne4 21.h6 Bg5+

22.Kb1 g6 23.f3 Nd2+ 24.Ka1 Qf6 25.f4 Qxf4 26.Bxg6 Kf8 27.Bxf7 Bxf7 28.

Ng6+ Bxg6 29.Qxg6 Bf6 30.Nxd5 1-0

[Event "Manila Meralco"]

[Site "Manila"]

[Date "1968.??.??"]

[Round "7"]

[White "Gligoric, Svetozar"]

[Black "Estimo, Nilo"]

[Result "1-0"]

[ECO "D36"]

[EventDate "1968.??.??"]

[PlyCount "139"]

[Source "ChessBase"]

[SourceDate "1999.07.01"]

[WhiteTeamCountry "ENG"]

[BlackTeamCountry "NED"]

1.d4 d5 2.c4 e6 3.Nc3 Nf6 4.cxd5 exd5 5.Bg5 Nbd7 6.e3 c6 7.Bd3 Be7 8.Qc2

h6 9.Bh4 Nh5 10.Bxe7 Qxe7 11.O-O-O Nhf6 12.Nf3 a5 13.Kb1 Qd6 14.h3 Nb6 15.

Ne5 Nfd7 16.f4 Qe7 17.g4 Nxe5 18.dxe5 Bd7 19.Qg2 a4 20.a3 Nc8 21.Rc1 b5

22.Na2 Nb6 23.Nb4 Rc8 24.Rhd1 O-O 25.Rc3 Rfd8 26.Bf5 Nc4 27.Bxd7 Rxd7 28.

Rcd3 f6 29.exf6 Qxf6 30.g5 hxg5 31.fxg5 Qg6 32.Nc2 Re7 33.Ka2 Rce8 34.h4

Nxe3 35.Nxe3 Rxe3 36.Rxe3 Rxe3 37.Rf1 d4 38.Qf2 Qe6+ 39.Ka1 d3 40.g6 Qe8

41.Rd1 Re5 42.Qg3 Qe6 43.Kb1 Rf5 44.h5 Qc4 45.Qxd3 Qxd3+ 46.Rxd3 Rd5 47.

Rxd5 cxd5 48.Kc2 Kf8 49.Kd3 Ke7 50.Kd4 Kf6 51.Kxd5 Kg5 52.Kc5 Kxh5 53.Kxb5

Kxg6 54.Kxa4 Kf5 55.Kb3 g5 56.Kc3 g4 57.Kd3 Kf4 58.a4 Kf3 59.a5 g3 60.a6

g2 61.a7 g1=Q 62.a8=Q+ Kf4 63.Qe4+ Kg5 64.Qe3+ Qxe3+ 65.Kxe3 Kf5 66.Kd4

Ke6 67.Kc5 Kd7 68.Kb6 Kc8 69.b4 Kb8 70.b5 1-0