There are no unbeatable chess players in the world, there never were and never will be. As well as there are no unbeatable teams. Everyone has his unlucky days. Even the great teams of USSR sometimes experienced losses. At this Olympiad Russian team looked like the incarnation of the former power of soviet chess. But the black day came...

Nakamura,Hikaru (2778) - Kramnik,Vladimir (2797)
USA - Russia

The position that earlier could be won easily and in several ways, was converted by Hikaru in a time-trouble into something intriguing and playable. Black has chances to survive.
48.c5
Of course, the Black's best card is the passed pawn.
48...f5?!
I suspect that this venturesome move ruins the game.
I think that it was better to activate the king at first, and then look at White's behavior. Here are sample variations: 48...Kg7 49.Ra7 (or 49.c6 f5 50.Ra7+ Kf6) 49...Kg6. Now there is a big divarication.
In case of 50.c6 f5 51.Kf1 Kf6 52.Ke2 Bf4 53.Rd7 (perhaps, more meaningful is 53.Ra4 Kg5 54.Rc4 Be5 55.Ne3 Bf4 and so on.) 53...Rxd7 54.cxd7 Ke7 55.Bc6 Bg5 56.Nb2 Kd6 57.Ba4 e5 58.Nc4+ Kd5 59.Nxd2 e4 White has no happiness.
The other way is principal: 50.Ra8 Rxa8 51.Bxa8 Kf6 52.Kf1 Ke5 53.Ke2 (53.Bg2 Kd4 54.c6 f5 55.Ke2 Bc7 56.Kxd2 e5=) 53...Kd4 54.c6 Bf4 55.Ne3 f5 56.Bb7 Kc5 57.Ng2 Bc7 58.Kxd2 Kd4 59.Ne3 Bb8 60.Ke2 Kc5 61.Kd3 Bc7, and again Black holds.
49.Ra7!
Cutting the Black monarch on the 8th rank.
49...e5 When you say "a"... 50.c6 e4 51.Bh3 Rc8 52.Ra6 Rf8
Did not help 52...Re8 53.Kf1 Bc7 54.Ra7 e3 55.Ke2 f4 56.Bg4 Re7 57.Nc3 Kf8 58.Bf3 (worse is 58.Nd5 Rg7 59.Bf3 Rg1) 58...Be5 59.Rb7 Rxb7 60.cxb7 Kf7 (60...Ke7 61.Nd5+ Kd7 62.Nb4 и Na6) 61.Ne4 Kg6 62.Nc5 Kg5 63.Nd7 Bc7 64.b8Q Bxb8 65.Nxb8 Kh4 66.Nc6 Kg3 67.Nd4 – later White accurately capture all Black's pawns.
53.Ra5 f4 54.Kf1
Too early is 54.c7? e3 55.Kf1 e2+ 56.Kxe2 f3+! 57.Kxd2 Bxc7.
But this was winning easily: 54.Rg5+! Kh8 (54...Kf7 55.Rf5+) 55.Rxg3 fxg3 56.c7. Apparently, the opponents missed this resource.
54...e3 55.Ke2 Rf6
As much as I searched, I could not find the escape anymore. Black bishop is seriously misplaced.
56.Ra8+ Kg7 57.Ra7+ Rf7
Also bad is 57...Kh6 58.c7 f3+ 59.Kxe3 Bxc7 60.Rxc7 f2 61.Bf1+-
58.Rb7 I leave out the alternatives. 58...Kf6 59.Kf3 Re7 60.Rxe7 Kxe7 61.c7 e2 62.c8N+! [62.Kxe2? f3+!] 62...Kf6 63.Kxe2

Black pawns gradually fall and we see a rare piece situation. It is known that two knights do not win against the king, but if we add bishops, the win becomes easy.
63...Ke5 64.Nb6 Kd4 65.Bg2 Be1 66.Nd5 Ke5 67.Nb4 Bh4 68.Nd3+ Kf5 69.Kxd2 Kg4 70.Ke2 Bf6 71.N1f2+ Kg3 72.Bf3 Bd8 73.Ne4+ Kh4 74.Ne5 Bc7 75.Ng6+ Kh3 76.Ne7 Bd8 77.Nf5 Bb6 78.Kf1 Kh2 79.Bg4 f3 80.Nh4, and Black resigned due to inevitable mate.

It is interesting that the decisive strike that ruined Russians was made by their former compatriot.

Grischuk,Alexander (2763) - Kamsky,Gata (2746)
USA - Russia
Gata made a big impression by his outfit choice in this round. It seems he used the famous formula of soviet singer Vysotsky: "I inadvertently exposed my biceps and even took off the jacket to be sure"!

Apparently, the previous games of the tournament and long defense this evening tired Sasha so much, that he lost any control of the situation. And so he lost the position that otherwise could defend blind or in blitz.
55.Be3
Not necessary. The run of the king gave an easy draw: 55.Ke1 Bf2+ (55...Bc3+ 56.Kd1) 56.Kd1 Ke4 57.Rh3! Bc5 (57...Kf3 58.Rh5=) 58.Rh7 Kd3 59.Rd7+ Bd4 60.Re7 Rh2 61.Re8 Ra2 62.Bc1 Rg2 63.Bf4 and so on.
55...Bxe3 56.Rxf5+ Kxg3
This endgame that is studied all through is not difficult to defend if one manages to keep the concentration...
57.Re5 Rf2+ 58.Ke1 Kf4 59.Re8 Ra2 60.Kd1 Kf3
Here the fracture happened.
61.Re7?
The easiest way of defending is to control d2 square - 61.Rd8 Bf4 62.Rd7 Bg5 63.Rd6=.
Did not lose 61.Rh8 Rd2+ 62.Ke1 Rd7 63.Rh3+!
61...Rd2+ 62.Ke1 Rd8!

Now Black knits the mating net as grandfather Philidor taught.
63.Rf7+ Bf4 64.Rf6
Or 64.Rf5 Re8+ 65.Kd1 (65.Kf1 Rc8) 65...Rc8–+.
64...Rc8
White rook does not manage to come to vertical "d" 0–1

Victory of Jakovenko over Robson on the 4th board could not help any longer. Americans caught Russia in the tournament table and got significant chances for medals.

Chinese are in a run for gold, too, as they defeated Philippines.

Ding,Liren (2695) - Barbosa,Oliver (2554)
China - Philippines

Black forgot to develop and got punished for that.
17.Nd6+! Bxd6 18.exd6 Qxd6
He could not hold the pawn: 18...Kf8 19.Ne5 Qxd6 20.Qg4 Rh7 21.Bxh6!.
19.Ne5
Most energetic.
19...Rg8
Too ugly is 19...Rh7. In this case White calmly continued to pressure 20.Bxb4 axb4 21.Re1 and stroke in the right moment - 21...c5 (21...Nf6 22.Bd3) 22.Qc2 Nf6 23.Nxf7! and so on.
20.Bxh6 f6 21.Bxg7! fxe5 22.h6
White gets a strong passed pawn for the knight.
22...0–0–0 23.h7 Rxg7 [23...Rge8 24.Qxe5!] 24.Rxg7 exd4 25.Rg8 Qh2 26.h8Q 1–0

Armenians pleased with their persistence. They collected themselves after the failures and won against the winners of the European team championship.

Aronian,Levon (2816) - Naiditsch,Arkadij (2712)
Armenia - Germany

It seemed from far away that Black would hold this endgame with opposite color bishops. But at close sight one can see the problems.
53.f4! Bh4 54.f3!
Both pawns on "f" are needed for the winning break.
54...Bg3
I also studied another standby: 54...Kd8 55.Bc2 c4 56.f5 Be7 57.f6 Bc5, but there is a problem - 58.f4 (too early is 58.Kf7? Kxd7 59.Kg8 Ke6 60.f7 Ke5 with balancing counter play for Black) 58...Bd4 59.f7 Bg7 60.Kf5 Kxd7 61.Kg6 Bf8 62.Kh7 Ke6 63.Kg8 Ke7 64.f5 Bh6 65.a3 a5 66.a4+-
55.Ke7 Bh4+ 56.Ke8 a5 57.Bc2 c4 58.f5 Bd8 59.f4 Bh4 60.Ba4 Bd8 61.Kf7!
Pawn d7 is not needed anymore.
61...c2 62.Bxc2 Kxd7 63.f6 Bc7 64.Ba4+!
It was not yet late to ruin everything: 64.f5? Be5!=.
64...Kd8 65.Kg8!
White wins the bishop and does not let black king into the rearwards. 1–0

This match did not escape the intervention of Fortune.

Akopian,Vladimir (2687) - Meier,Georg (2648)
Armenia - Germany

44.Qd4
Of course White stands better but Black did not have to lose in one move.
44...exf3??
And Georg resigned when he noticed the mortal check on g4.

Azerbaijan did not manage to return to the top. Their leader experienced unpredicted loss. But they managed to hold the draw in the match.

Mamedyarov,Shakhriyar (2729) - Socko,Bartosz (2635)
Azerbaijan - Poland

White threatens the mortal pin on vertical "d". How to unpin?
27...Qb8?
The answer is wrong. Black forces white knight where he wanted to go himself.
Right is 27...Qc8! 28.Rd4 Rc5, and the shift of the knight to e3 does not succeed due to 29.Ng4 Re8! 30.Nxh6+ (not good 30.Rxd5 Qxg4) 30...gxh6 31.Rxd5 Qg4 – Black has pretty defendable position as there is no 32.Qxh6? Rxd5 33.Rxd5 Re1+ 34.Kh2 Qh4#.
28.Ng4
Now the choice of Black may be wide but eternally sad.
28...f5
Black was left without a piece also in case of 28...Qc8 29.Ne3 Rc5 30.Rd4.
If 28...Rc7 29.Rd4 Rcd7, then 30.Nxh6+! Kh8 (too bad is 30...gxh6 31.Rg4+ Kh7 32.Qc2+ Kh8 33.Qb2+ f6 34.Rxd5!) 31.Qg5 f6 32.Qg6 gxh6 33.Rxd5 Rxd5 34.Qxh6+ Kg8 35.Qg6+ Kh8 36.Qxf6+ Kg8 37.Rxd5 Rxd5 38.Qe6+ with a winning queen ending for White.
29.Rd4 fxg4 30.Qxc3!
The resource that was apparently missed.
30...Nxc3 31.Rxd8+ Qxd8 32.Rxd8+ Kh7

Shakhriyar converted the extra exchange in his artistic manner.
33.Kh2! Nxa4 34.Kg3 Nc3 35.Kxg4 a5 36.Kf5 b5 37.f4! b4 38.g4! b3 39.g5 hxg5 40.fxg5 g6+ 41.hxg6+ Kg7 42.Rd7+ Kg8 43.g7! Kh7 44.g6+ Kg8 45.Kg5
White mates. 1–0

Ukrainians, as it was predicted, rose from the ashes. Solid Frenchmen could not oppose them with anything. The most charismatic player of the Olympiad pleased with his creative play.

Ivanchuk,Vassily (2769) - Vachier-Lagrave,Maxime (2686)
Ukraine - France

15...b4
Maxime is literally forcing his opponent to attack.
16.Nd5!
A sacrifice in Tal's style.
16...exd5 17.exd5 Na7 18.Nd4!
The meaning of the position is not in the concrete bright variations, but in the fact that Black's king does not have a comfort shelter, so White can calmly and methodically develop the pressure.
18...Bxd5 19.Nf5 Nc6
There was sense in 19...Nc8, for example, 20.Be4 Bxe4 21.Rxe4 Ra7 22.Rfe1 Qc5!.
20.Be4! Bxe4 21.Rxe4
Now the set up with the rook on a7 does not save. But there is another solid idea...
21...Kf8?
A step to the edge. He should have created a solid construction by 21...Rd8! 22.Rfe1 Rd7, and in case of 23.Qe2 the king can go to the queenside: 23...d5 24.Re3 Kd8!.
22.Rfe1 Re8 23.Qe2! Rh7
The only way not to be mated immediately.
24.Qg4 d5
More persistent 24...Qd7!, for example, 25.g3 Nd8 (25...hxg3? 26.Rg1) 26.Nxe7 (absence of the pawn on d5 plays a role in a key variation 26.gxh4 Ne6 27.Rxe6 fxe6 28.Rg1 Qc6+! 29.Kh2 Qxc2+ 30.Kh1 Qc6+ with perpetual) 26...Qxg4 27.hxg4 hxg3+ 28.Kg2 Ne6 29.Nd5 Kg7 with a counter play on the vertical "h".
25.R4e2 Qb6
Fruitless is 25...Qd7 26.g3 Nd8 27.gxh4 Ne6 28.Rxe6 Qxe6 (28...fxe6 29.Rg1) 29.Rxe6 fxe6 30.Qg6+-
26.g3!

The opening of vertical "g" finished the game.
26...Nd4 [Or 26...hxg3 27.Qxg3 Rd8 28.Rg2!] 27.Nxe7 Nxe2 28.Qg8+ Kxe7 29.Rxe2+ Kd6 30.Rxe8 hxg3 31.Qf8+!
The only way to the aim. The false note could be 31.Rd8+? Kc7! 32.Rc8+ Kd6 33.Qf8+ Ke6!.
31...Kc6 32.Rc8+ Kd7 33.Qe8+! Kd6 34.Rd8+ Kc5 35.Qe3+ Kc6 36.Rd6+!
The bright finale of the brilliant game. Bravo! 1–0

Nothing unexpected happened in the women's section. The only surprising thing was that low rated pare Kazakhstan – Uzbekistan managed to the leading matches. Kazakh girls won and as a reward got an opportunity to face China on the next day.
In general, in the 8th round the strongest teams methodically overplayed those that are weaker. Of course, they also had some luck.

Hou,Yifan (2599) - Skripchenko,Almira (2442)
China - France

The whole game Elmira was fighting as a lioness that protects her baby-lions. But the power left her after the time control.
41...Kh5?
Horrible blunder. Accurate move 41...Ra2! kept a big intrigue. Yifan would have to work a lot to win. In the analyses I did not at all find a way to win for White. Perhaps, because there is not. Black threatens the rook escapade to a1, and the exchange sac on c7 is far not that perspective as it may seem.
42.Rxc7! Qxc7 43.Qd1+! and on 43...Kh6 follows 44.Qc1+ winning the rook...nothing to do but resign.

Kosteniuk,Alexandra (2489) - Soumya,Swaminathan (2271)
Russia - India

1.e4 c6 2.d4 d5 3.e5 Bf5 4.Nf3 e6 5.Be2 c5 6.c3 Nc6 7.0–0 cxd4 8.Nxd4 Nxd4 9.cxd4 Ne7 10.Nc3 Nc6 11.g4 Bg6 12.f4 Qd7

When the opening is studied back and forth, when you know all the key ideas and remember some lines, it is easy and comfortable to attack.
13.f5! exf5 14.h4! fxg4
Could lead to very interesting complications 14...h6 15.h5 Bh7 16.gxf5 Bxf5 17.Rxf5 Qxf5 18.Bg4 Qh7 19.Nxd5 Qe4! (19...Rd8? 20.Nc7+ Ke7 21.d5 Nxe5 22.Qe1! Kf6 23.Qf2+ Ke7 24.Qe3+-) 20.Nc7+ Kd8 21.Nxa8 Nxd4 , and here ... no way to White's win is seen.
That's why on 14...h6 I recommend easy 15.Bd3! with strong initiative. On 15...fxg4 there is 16.Bxg6 fxg6 17.e6!.
15.Bxg4 Qd8
Computer recommends 15...Qc7 , but it shows that there is no equality for Black: 16.h5 Be4 17.Nxe4 dxe4 18.Qc2! Rd8 19.Be3, and White capture on e4 with the queen.
16.h5 Qh4 17.Kg2 Be4+ 18.Nxe4 dxe4 19.Bf4
Harder is 19.Rf4! , for instance, 19...Qd8 20.d5! Nxe5 21.Qa4+ Ke7 (21...Nd7 22.Rxe4+ Be7 23.d6) 22.Rxe4 Qd6 (22...f6 23.Rxe5+) 23.Bg5+ f6 24.Rxe5+ Qxe5 25.Qd7#.
19...Rd8!
There is now life on Mars.
20.Bg3 Qg5 21.Qb3
Leaded to a win 21.d5! Be7 22.d6 Nxe5 23.Rf5, but it is impossible to find at the board.
21...Rxd4 22.Qxf7+ Kd8 23.Qe6 Kc7 24.Rad1?!
A mistake. It was right to start from 24.Rf7+!.

24...Bc5?
The last mistake. After accurate 24...Rxd1! 25.Rxd1 Bc5 palm trees would grow on the red planet.
25.Rf7+ Kb8 [Or 25...Kb6 26.Rxd4 Bxd4 27.Qb3+] 26.Rxd4 Bxd4 27.Qd7 Qd2+ 28.Kh3 Qxb2 29.Qc7+ Ka8 30.Bc8! 1–0

Gunina,Valentina (2507) - Karavade,Eesha Sanjay (2371) [E15]
Russia - India

White has initiative but there is still a lot to play.
31.e4! Rb4?
After this mistake not so much is left to play anymore...
It was right to go 31...Rb1+ 32.Kg2 Nb4 33.Nd6 Kf8 and so on.
32.Rc1!
No trade of rooks, no life for Black's knight!
32...Ra4
Only in the last moment she noticed that 32...Rxe4 33.Nd6 leads to mate or loss of one of the pieces.
33.exd5
The rest was not necessary. White won.

China and Russia with parallel courses go for gold and silver medals. And it si not yet clear who will join them at the pedestal.

We'll see...