he made a joke. :) <acirce> know perfectly well the correct spelling, but choose the Swedish one on purpose...

<I said close to useless, but of course it has a relative usefullness, when you have the TBs at your disposal. Depending on the position at hand.>

There are open endgames which Rybka 3 handles well without TB-support. The point is that if Rybka can see far enough (and it often can in simple, open endgames), it doesn't need specific knowledge or TBs to play good moves.

<However, <rybka 3 <<< generally >>> handles endgames better than the 2700+ players Carlsen mostly plays against> is a bit of a stretch to me.>

It may sound a bit farfetched, but this view is actually based on my own experiences when analyzing hundreds of games (usually every move after the opening) between 2700+ rated players using Rybka since early 2006. You might be surprised to learn how often even strong GMs make mistakes (or inaccuracies) in the endgame (and even in simpler endgames). I think there are many psychological factors involved here. Time can also be a factor, of course.

<1. I still use a 32 bit 2.1 version of rybka - and it is not up to the standard of the recently released Deep Rybka 3.>

Rybka 3 is significantly stronger than 2.1 (or 2.3.2 for that matter), as shown through independent testing by CEGT, CCRL and SSDF.

<2. Players often play on increment, even in classical games, with just a few minutes on the clock, and are tired and inaccuracies may, and do, frequently occur.>

Yes, but inaccuracies (or outright bad moves) also occur when they're not under time-pressure. One of the computer's strengths is, of course, that it doesn't get tired.

<3. For humans who know the endgame fundamentals, the < strongest move> is the surest and least complicated way to a win>

No, not necessarily. The strongest move could also be the move that leads to most complications. Computers aren't too concerned with tactical or complicated positions, but humans often prefer to simplify things or play simple, but strong moves when they've got the advantage. Magnus often prefers to play practical moves that suits his style, not necessarily the very best move (it can be seen in his games and he's explained this in interviews, after being asked:"Why didn't you play the stronger move X?").

<It even clouds the issue, because the theoretical win that follows from Kxa6 is the safest and most efficient route to a win>

Yes, for a human perhaps. It's probably the reason why Magnus played Kxa6.

<The specific line from this position is quite simple, and if you play it out on ANY ENGINE, incl. Rybka 3, you will see the eval increase to +10 and higher, 6 0r 7 PLY further down "the line." (Kb3)>

The same also goes for b4 of course (I've played through it's PV). And the reason why b4 has a higher eval is that Rybka sees that this move will lead to a bigger advantage in a shorter amount of time. But like I said: Both moves are good. It's just that Kxa6 appears simpler and more practical for a human. But the issue here is whether it was the strongest move, not the most practical, and Rybka's evaluation and PV indicates that b4 gives black a bigger advantage in a shorter amount of time.

<4. Terms like <objectively strongest> should be put in perspective, re the OTB circumstances the players play in: even IF the engine finds a so called "better move", it may prove a more risky one, and as a player you want to avoid such lines, and therefore it is not better per se.>

Objectively, it is. That's the difference between a subjectively strong move, and an objectively strong move :)

<5. ... Even as a dry analyst, with your TBs on your lap and a state of the art calculating beast, evals are merely floating on bobbing waves, heavily changing with each passing (4-6) PLY. This often becomes more apparent when approaching certain endgames like the one in Yue-Carlsen.>

I don't simply look at evals, but on the suggested main lines as well. It's natural and perfectly logical that evals increase as you get closer to a clearly won position. If the evals go up and down, it's usually because the players don't follow the suggested moves, not because the computer changes its mind constantly.

<Of course <rybka is <<< NOT >>> close to useless>, in many type endgames, but then again in many it *is*. (I see that <sheaf> has provided some material.)>

I've seen endgames (typically closed) in which even tablebases won't help much, but this is a rare occurence (you can also find examples on the Rybka forum). In practical play, however, I very rarely see Rybka suggesting bad moves when using TBs.

<If I had the time I would post some examples, but then bare in mind I only operate the inferior, dressed down 2.1 version of <Rybka>, so I can not pass specific judgement on Deep Rybka 3 on a Quad core.>

I don't use a quad core, I use an octocore :) (8 cores). I also use the 64-bit version, but this only means that Rybka searches deeper in a much shorter amount of time compared to Rybka 3 (single CPU 32-bit version). It doesn't affect its evaluation. However, the multiprocessor version does sometimes produce other PVs than the single CPU-version, and that's because the parallelization code isn't entirely deterministic.

<Keep <interrogating> the machines, at ANY stage of the game, is my "motto.">

Certainly :) That's part of the fun. Simply looking at evals without playing through the main lines and trying to understand them isn't that interesting.

Anyway, I don't want to start a long discussion about this. I don't post on this forum very often (on the contrary), so I might not be able to follow up this discussion anyway.

<You are 100% correct and your explanation was perfect. I thought about addressing this point, but I'm glad I didn't because your reply was better than anything I had in mind. In fact, I'm going to copy your post to my forum for future reference.>

Well, I'm glad you found it useful :)

Each player has a laptop with a blank board and a list of the moves played?

I don't think that they get a list of the moves. The last move simply appears on the screen for a while and then disappears. The notation for the last move may stay on the screen as well.

You indeed post rarely, but when you do you go about your business very thoroughly, and expertly.

What I enjoy mostly when all is being said and done, is the process of:

being CHALLENGED to IMPROVE ON my overall- and specific- understanding on a subject like this;

<computer's relative strengths and weaknesses, and how to optimize my understanding- and ways of using- the information it provides.>

isn't today a rest day??????