Tuesday, January 13, 2015

Cochrane Gambit is Safe

John Cochrane, economist, lawyer, or chess player?

Wait, there is an active Chicago academic economist named John Cochrane:

And of course who can forget this guy:

But we're talking about the 19th-century Scottish chess player:

Who invented the Cochrane Gambit (for White) of the Petroff Defense (for Black) with this game.

The name Cochrane.

Cochrane is an interesting surname. Turns out it has three different Scottish/Irish origins:

Another Cochrane in popular culture is Zefram, fictional inventor of Star Trek's "warp drive".

A new Cochrane Gambit line, for White.

1 e4 e5 2 Nf3 Nf6 3 Nxe5 d6 4 Nxf7 Kxf7 5 d4

Now Black has options, with a burden to demonstrate White's gambit unsound. Stockfish seems to have demonstrated that my previous conjectured refutation, 5...Qe8 6 Nc3 d5 7 e5 c5, still leaves White with enough for a draw by repetition. The right plan for White is to ignore d4 and go after the king with 8 Be2, breaking the pin on e5.

(For reference, the previous line went 8 Bc5+ Nc6 here, not good enough for White). Now pretty much forced is 8...cxd4 9 exf6 dxc3. White has traded away the strong center for "a bone in Black's throat" on f6.

10 O-O now breaks the pin on e2, and with 11 Re1 coming next, there are enough threats against Black's king and queen to compensate for the knight-for-pawn material deficit.

A sample short perpetual (Black has no better) is 10...Qc6 11 Re1 g6 12 Bf3 Be6 13 Rxe6 Kxe6 14 Bg4+ (Kf7 15 Bf3 Ke6 ...):