An irrefutable argument in your case appears to be one that you will continue to believe in, no matter what contradictory experience shows.

32.e7+ would offer Naiditsch a draw-chance. And Rybka seems to like 32.e7+

This is my suggestion:

<When reading these comments I feel that our creativity to aim for a victory was somewhat lacking. Did we improve our position with Bd2/Bb4 accepting destruction of our Q-side pawn formation?>

It is hard for me to say whether we improved our position with 22.Bd2, 23.Bd4 or not. I have 5 engine analyses with 22.Bd2 Rd8 23.Bb3 and the evaluations ranged from [-0.50] to [+0.10] with an average evaluation of [-0.09]. I have 14 analyses for 23.Bb4 a5 24.Bb3 with evaluations ranging from [-0.14] to [+0.14] with an average evaluation of [-0.01]. I have 64 analyses after 23.Bb4 Nxb4 24.axb4 Rd4 with evaluations ranging from [-0.55] to [+4.96] with an average evaluation of [+0.31]. If I delete the 4 analyses with 24...Bb6 with evaluations above [+3.25], the upper bound becomes [+2.02] but the average evaluation remained the same. So I would say that (1) 23...a5 was a better move than 23...Nxb4 so the destruction of our q-side pawn formation was more than compensated for by other aspects of the position and (2) 23.Bb4 provided an irresistible temptation for GMARK to play 23...Nxb4 and so it was our best practical chance. If you think that this approach was lacking in creativity then I guess that depends on your definition of creativity. What do you think would have been a creative approach under the circumstances?

<I am confidant that the result of any fair assessment of this line will be in agreement with my findings. It would also discover that any engine could have run out this position without any human assistance to a dead draw>

My records show that 9 different engines found 24...Rd4, and I have 34 engine analyses with what we thought would be the most likely line played, 24...Rd4 25.Re2 Bh4 26.g3 Bg5 27.Bc2 Rf8 28.h4 Be7 29.Bb3+ Kh8. The evaluations for these lines ranged from [-0.16] to [+2.02] with an average evaluation of [+0.40]. Depending on which engines GMARK was running <and the search depth that he allowed them to run>, even this slight advantage for White might not have been to his liking.

<For the sake of our teams playing record it should be pointed out that our early opening goal was to refute C67. But our analysis confirmed the theoretical known draw lines as irrefutable.>

I don't know that it was the team's goal to refute C67 or whether the team had any opening goal at all other than the general one of achieving a better position from the opening. It was <my> goal (among others') to see if some new ideas favorable for White could be found in C67 that would improve White's practical chances, but that's a long way from finding a refutation of C67; trying to find a refutation of C67 (and practically any other mainline opening) would be quite a stretch. And, anyway, that's not what the team decided to try to do. So, given that this was not the direction that the team decided to go, I don't think that there was any analysis that "confirmed the theoretical known draw lines as irrefutable." Pessimistic thinking or acceptance of conventional current perhaps, but no definitive analysis.

<This findings led us to adopt the C65/d3 line to prolong the inevitable draw as per historical game records.>

I don't know what historical records you are referring to. The ChessTempo database has 2,700 games starting with 1.e4 e5 2.Nf3 Nf6 3.Bb5 Nf6 4.d3and only 44.2% of them ended in draws. The 365Chess masters database has 1,345 games starting with 1.e4 e5 2.Nf3 Nf6 3.Bb5 Nf6 4.d3, and 49.7% of these ended in draws. Given than in both databases the number of decisive games is greater than the number of drawn games leads me to conclude that a draw in this line is far from inevitable.

<It is my understanding that we diverted from the solid but equal positions proof red with deep engine analysis as a result of DS's recommendation to accept an apparent inferior line from a human perspective but tactical sound and more challenging for us to hold a draw.>

My persistence not to accept assumptions that plunder moves are the deciding factor in high level correspondence should also be our guiding factor for our game strategy.

It stems from my contrary view of yours never plan for a mistake from your opponent.

You seem to be annoyed from my insistence that high level correspondence games are not won as a result of a plunder move.

Yes there are exception like I made by sending a wrong move because of a mix up of addresses. Or in our case one player decides to close out the game for a specific reason deemed to best.

But if you replay a won game from top level correspondence to find the reason for loosing it most likely could not even be explained without hurting the losers feelings.

Many times after a game was completed I was asked why did I loose, I thought I was winning? A short answer would have been ; your playing ability is simply inadequate for this level or I got lucky.

Your reply is not unexpected. Just trying to stay positive I like to add that game results from public data bases are very misleading at face value and should not serve us to follow them blindly. This also holds true for shallow engines evaluations.

<But if you replay a won game from top level correspondence to find the reason for loosing it most likely could not even be explained without hurting the losers feelings.>

If you were to post a game that you either won or lost, seemingly without an error on either side, would it hurt your feeling if an error were to identified?

I have only lost one game due to a mailing error and this was my only loss in all of my correspondence playing over many years.

< would it hurt your feeling if an error were to identified?>

We seem to differ about the definition of the word error.

Because I think of a plunder when I see the word error but agree with your perception that it takes an erroneous tactic or strategy to give away a draw.

<My opinion is that the failure to find an error must be simply an inadequacy in the analysis.>

Well accepted moves or move over time have been identified as questionable and replaced with more effective moves or plans.

I can think of many "erroneous" opening ideas which have been replaced and discoveries are still ongoing. Is this not part of the ever evolving opening theory?

<DanLanglois: <kwid: Well,well, what happened to the creation of force imbalance?>

Well, well, what is 'force'?

<I rightly or wrongly thought that chess is a battle between two armies of equal strength.. >

What is 'strength'?

<I thought that white will try to occupy the most strategic hill side called center..>

Why is the center the 'most strategic'?

.. >

<DPLeo:>

Dave,

Watching a chess engine choose it's move 29 is like watching a race between a tortoise and a hare.

It is easier for both an engine and humans to find the tactics and flaws of 29...Ke8 and 29...Exg5 than it is Pb5 negating the tactics against his c6 square but overlooking and underestimating the strength of repositioning our bishop to g4.

Rybka understands the concept even less than Stockfish. If he uses a laptop and not a twelve or 24 core workstation, 29...Pb5 looks possibly survivable after 3 days of running.

A minor point. The word you want here is "blunder", not "plunder".

And 23.Bb4 was masterful. When <DaringSpeculator> suggested this I thought that he was nuts. Here we had just obtained the 2 bishops as partial compensation for our pawn deficit and not only were we going to give up this advantage but accept doubled isolated b-pawns to boot! Madness I tell you. But the appeal of 23...Nxb4 was apparently too much for GMARK to resist (as I indicated it would have been for me), and I don't think that he fully appreciated (nor did I) the need for his Bf2 to get back to keep an eye on e7 and that 24.axb4 cut off his ...Bc5 just like our earlier 20.Rxe4 had cut off his other alternative, ...Bh4.

Finally, this game seems to have the types of positions where deep engine analysis is not only a benefit but a <requirement>. Time after time (but not any more!) the engines I've been using had indicated a near even evaluation at reasonable search depths but indicated increasingly favorable evaluations for White as the search depth went deeper, deeper than I normally do. And different engines gave different evaluations and lines. Because of GMARK's busy schedule and likely limited computer resources (certainly compared to our team!), he probably didn't have the time to run either multi-engine analyses or allow his engines to achieve adequate search depths. So I would say that this is an instance of taking advantage of one of our strengths.

I sure hope that he has the time and inclination to participate in a review of the game so we can ask him questions as to his playing approach and the reasons why he selected or didn't select certain moves. Maybe we can even ask him if he has read any of Reinfeld's books. :-)