Still not believing it!

 c3 looks interesting

1. c3 Qxb3 2. Rxe5 f6 3. Qg3 fxe5 4. f6 g6 5. f7+ Kf8 6. Qxe5 Bf5 7. Qh8+ Kxf7 8. Qxa8

though not "winning" it leaves white ahead slightly. plus, if you can trade queens then you've got a king & rook v. king & bishop end game.

Let's analyse this from scratch for white.

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Analysis "Pros, Cons and Plans"

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White Pros: Active pices, Good amount of Atacking pices over blacks king, Rock behind an advanced pawn, "Iniciative", good comunication between pices.

White Cons: Behind material, Black side have a good bishop vs white un-posted knight.

Black Cons: Very misplaced pices especially the queen, bad comunication between pices.

White's Plan: Use the iniciative and active pices for an atack.

Black's Plan:Exange material specialy "queen's" if possible and head for an endgame keeping his edge on material.

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Design "Making it happen"

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We know that we want to atack, a basic tactic them when you are planing an atack its to "open lines" into enemy's king and actually 1.Rxe5 does that it open a line for our f pawn to avance further into enemys king position using the advantage that we already have a Rook behind it. lets say:

1. Rxe5 f6 2. Qg3 fxe5 3. f6  but this line gets refuted by 3... Qg4 4. Qxe5 Rf8 5.Qxd5+ Qe6 6.Qxe6 Bxe6 and this with carefull play from both players should be a draw.

Now we saw that retreting in the midle of the atack wasn't an option since it gave black chances to get his queen back to the defence of his king, so we need other tactic theme "removing/deflecting the defender" we need to take that queen away from the defense of the g4 square. we said in the pre requisits of the software... ehem i mean on the analysis part that the misplacement of the Blacks queen was a factor since she dont have to much place to move, also that our knight was not that useful at the moment so we can exchange some resources for others in this case material for time and quality. let's follow the next line.

1. Rxe5 f6 2. c3! Qxb3 3. Qg3 fxe5 4. f6 g6 5. f7+ Kg7 6. Qxe5+ Kh6 7.
Qf4+ Kh5

And his king its exposed if you ask me that worth more than an inactive knight now being on blacks shoes and knowing that taking that knight it isnt so much of a bright idea he can chose to play 2....Qc4 instead of 2...Qxb3.

3.Qg3 fxe5 4.Nd2!

We can't play f6 right away since it would open free the g4 square for black's queen.

4...Qe2 (trying to get closer to the defense) 5. f6 Qg4 (queen reach g4 but to late since we can move with tempo developing more atack over blacks king)6. Qxe5 Qe6 7. Qg5 g6 8. Nf3 Rf8 9. Ne5 Be8 10. Ng4 Kh8 11. h4

And the passed pawn and activity of white pices added to the iniciative should be winning.

So what if we play c3 first. it would go like this.

1. c3! Qxb3 2. Rxe5 f6 3. Qg3 Re8 4. Rxe8+ Bxe8 5. Qd6 Qxa4 6. Qxd5+ Bf7 7. Qd8+ Qe8 8. Qxe8+ Bxe8

This position its cleary wining for white too.

As conclution we can see that the key move its c3 to remove the queen from the defensive square g4 it doesnt matter if we play Rxe5 1st.

Anyway feel free to post any correction over my analysis.

I'm for Rf4, even though it allows the advance of a pawn from black, it activates the rook and will allow for a kingside attack with the rooks and the queen. I can't see much wrong with it, but it's a quick glance.

Phil,

Why are you so shocked that 1.c3 should turn out to be winning, if that is the move Rybka suggested? Did you think that black gets the knight for free?

Azoth,

Yes, so obviously 1...Qxb3 is a blunder. You only need to analyze a few moves to see that white gets a free rook and is up the exchange or black recaptures on e5 and white gets enormous pressure. But the black Queen does have one square: c4. So after 1.c3 Qc4, the ...Qg4 plan seems to work out the same as in the 1.Rxe5 line.

So why would Rybka be so set that c3 has to happen first that it gives 1.Rxe5 a question mark? There is still something we are missing and I can't put my finger on it. I wonder if Phil's analysis will answer this.

Wow, now I have really confused myself. Now 1.Rxe5 looks good:

1.Rxe5 f6  2.Qg3 fxe5  3.f6 Qg4  4.Qxe5 Rf8 (4...Qe6  5.Qg5)  5.Qxd5+

If 1.c3 Qc4 and then the same line as above, 6.Qxd5+ isn't possible because of 6...Be6. Of course, in the 1.c3 line, white gets to play 5.f7+ and then let his Queen settle on f4: 5...Kf8  6.Qxe5 Qe6  7.Qf4.  This way, white gets to keep the pressure up. White clearly won't be able to force the pawn to promotion, though, so I guess the advantage comes in the form of what white will be able to get out of the position with this pressure.

In the 1.Rxe5 line, white is not allowed the plan of f7+ because black has the resource 6...d4 and white will not be able to keep any pressure on f7. This is the closest thing I have found to an answer for why Rybka prefers 1.c3 over 1.Rxe5 so much, but with the line I posted at the beginning of the post, it seems like white can win the position after 1.Rxe5 as well.

So, in closing, I still have no idea what the f is going on.

Truly some amazing analysis. Some of it was a lot better than I did in the game when it was actually played. First up, Rybka gives Rxe5 as 0.18 while c3 is 2.13 so there is an obvious difference. Some hit upon the Rook on a8 as being the key to why one can even consider offering the knight at b3, I was happy that I was offering the pawn at a4 :) , never even put the undefended rook together with a knight sac as a line.

So now, I'll give the engine's word as it stands, I am still trying to refute the line, but alas I think Madam Rybka will prevail :)

I hope everyone realises to use the move list to get to the analysis :)

Looking forward to thoughts and opinions, there may yet be a bust, but please don't be too disappointed if we don't, Madam Rybka is pretty damn good.

Dear Phil,

Thank you for sharing this excellent example!

For sure only a GM or a chess engine to see the winning move and not the obvious one... 

I am just delighted to have actually played a game where such a problematic position occurred :) Never mind that I didn't see the solution :( I didn't even see the problem :)

Great example.  I wish I could give you the win but, I can not.   Only a agreeing comment on Qxe7+.  Or maybe Ref3.

@TonightOnly

Please follow my analysis and you will see that the Qc4 variant its covered.

@ Phil_from_Blayney

I still belive that after 1.Rxe5 f6 2.c3 the game its winning for white.

@ Azoth, I think you are right. I think I included this line in the move list where Rybka ended up assessing it as 0.98 and seeing how engines have greater difficulty assessing endgames, there may be drawing chances for Black. But in reality, it just means I missed c3 twice :)

Aha! The Queen can be kicked from the fourth rank!

I don't know why I never tried 2.Nd2, even after Azoth included it in his analysis. This is a pretty deep idea. I couldn't imagine finding this in a game.

Yes, but only as part of the 1.Rxe5 line, so the point was missed. In the 1.Rxe5 line, the black Queen is not denied the g4 square because, as you pointed out, black has 4...Qe2.

It may very well be.

As I pointed out in post #30, 1.Rxe5 may be winning for white even without 2.c3. However, it has been shown that the best plan by far is 1.c3 2.Nd2 and 5.b3, denying the black Queen the g4 square and forcing 6...g6. This is the answer. This is why Rybka gave 1.Rxe5 a question mark and scored 1.c3 so well.

BTW Phil

It seems pretty unfair that you should get a question mark after your move just for not being able to see this idea. I think Rybka should get off its high horse. Just because it's the best chess playing entity in the known universe doesn't mean it has to make the rest of us feel bad.

 That is why the inventors of Rybka decided that she was female. As all of us that are married and with girlfriends will testify, you can't win an argument with a female :)

N E V E R

Don't even try... 

Chess players with girlfriends? I thought we agreed to be ignored by that half of the world when we signed on. I guess we should all get ourselves to Blayney...

Rf4 corners the queen!