I think ...Ng4 is a good idea, but Black missed a golden opportunity to play it three moves earlier. 11...Ng4! is very good for Black -- he'll get in ...f5 without problem, and probably exchange the Knight for the Be3, which has nowhere good to go. After 12.Bd2 f5 Black is on top.

But it's subtly different on move 14. The retreat ...Bf8 has given White's Bishop a square on g5, and he can use it. He can also attack Black's Queen with Nb5, which is awkward. So something like 14...Ng4 15.Bg5 f5 16.Nb5 Qb8 is in White's favour. 15.Nb5 at once may be even stronger, and in this line the White Bishop can even drop back to d2. And a5 can be nasty, even without a target on b6.

But Black *does* have an interesting Knight move on move 14. With the other Knight. 14...Nf4!? is a nice trick: 15.gxf4 exf4 wins the piece back, and if Nb5 then ...Qd8 is fine. Plus, it justifies the earlier moves ...Re8 and ...Bf8.

I don't think 14...b6 is *very* bad, although Reti makes the White win look inevitable. Perhaps it is: I can't find any real improvements for Black later on. But it would take a great player to recognize it as a losing move - or a winning opportunity.

Black had drifted over the previous few moves. 14...Nf4 still leads to dynamic equality, your 14...Ng4 is a better try too, although White has an edge.

The whole line went out of favour at the start of the 20th century. Nimzowitsch revitalized the Hanham Variation, where Black plays ...Nbd7 before ...Ngf6, avoiding the Queen exchange.

That became the Philidor mainline for almost a century, until the ...Nf6 line was rediscovered (and renamed) in recent years. In the spirit of other Kramnik-style openings, it's now thought that White gets nothing special by exchanging Queens.

The game starts out in classical style, with a Philidor's Defense to the double king pawn opening. Black promptly transfers his queen's knight to the kingside and castles short in just eight moves.

Richard Reti seizes on such an early commitment and does just the opposite with his knights and fianchettoes his king's bishop on the long diagonal. Then Reti turns loose both knights (Nc3 & Nc4?!) and pawns (10.a4!?) supported by both bishops to terrorize Black on the queenside.

Reti shows keen tactical foresight (the exchange sacrifice 17.RxBa6 relieves the pin and allows the discovered attack 18.Nxd6! to remove a critical Black center pawn allowing future White expansion) to maneuver threats and exchanges that reduces material. This generates two safe, connected passed pawns on the queenside ready to march forward. Meanwhile, the cozy pair of Black knights and king sit peacefully as defeat is eminent on their distant border.

This was certainly an impressive performance by Richard Reti. With the castled Black king surrounded by four pieces, Reti was prepared for battle on the queenside in ten moves from a double king pawn open game. His tactical acumen uses each piece, makes threats, and simplifies into an easily won endgame.

If instead 16...QxNc4 17.RxBa6 regains the minor piece with x-ray defense (the White Q protects the loose White R) and eliminates the Black battery.

If instead 16...BxNc4 17.bxQc7 BxQe2 18.NxBe2 restores the piece count and yields an extra pawn for White on the 7th while saddling Black w/an isolated a-pawn under fire.