I am re-posting this from a general chess.com forum where some asked about the ECO for the Jobava System.

https://www.chess.com/forum/view/chess-openings/eco-code-for-jobava-london?page=1#last_comment

The Answer is ECO D01 - Let me explain

The ECO (Encyclopedia of Chess Openings) recognizes the 1957 game between the late Russian Ratmir Kholmov vs the renowned Ukrainian Efim Geller. Kholmov, known as an attacking player but more notably with the black pieces, of course tried the attacking Jobava against Geller. Although not known at that time as Jobava, The ECO recognizes the game in the number 1 variation of 1.d5 d5 2.Nc3 Nf6 3.Nf3 where Bf4 is played on the 3rd move although in many games the Black pieces have already played the hyper-modern g6. Interestingly, the JLS (Jobava London System) was mostly introduced (to me anyway) as a new, worthy and attacking challenge against the hyper-modern g6 defense.

Chessgames, a good database website, but lists this game as A45. When you look up A45, the first variation gives 1.d4 Nf6 2.c3 with 2.Nc3 d5 and sends you to D00. As I am sure you have seen, D00 does not give 3.Nc3 but Bf4, Bf5, e3 etc. True JLS players will play 2.Nc3 preparing for and immediate e4 if 1...Nf6 is not followed by d5.

Those of us interested in Beth Harmon's MCO and the 4-volume ECOs' especially as her study guides know that ECOs' are often fickle. But for a condensed database of openings, it is still a go-to source.

Hence, I look forward to an expansion of D01 in future ECOs', MCOs' or other database recognition. Hope you enjoy the game! Thanks the ChessGames!

-Two Cents

The 'NEW JOBAVA' London System

Super Admins