It seems that the K.I. reversed positions where the white pawn winds up on e5 are sort of the linear descendents of the French advance positions in which Nimzowitsch let d4 go and overprotected e5. If they are the leading examples of the theory overprotection would seem to be of limited application.

Condider the following two diagrams. It is Black to move, and the diagrams differ only in the position of White knight.

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At first glance, I would actually prefer the former position (as White), because the d3 pawn is for taking in the latter and overall the knight just seems to be in a way on d2. But, the former position is a loss for White while the latter is a win! The difference is that in the latter position the square e4 is over-protected by that awkwardly looking knight on d2, and that turns critical, because after <1...Rxc4 2.Nxc4 Rxc4! 3.dxc4 Qe4 4.f3 Qe3+ 5.Kh1 Qf2 ...> White can not avoid being check-mated!

Now the difference between the two positions comes to light if White takes by the d3-pawn first: After <1...Rxc4 2.dxc4>, in the former position Black <3.Qe4...> once again instigates the mating process, while in the latter position the all important e4-square is still protected by the (formally over-protecting) knight.

The punchline is this: In the first position, the pawn on d3 can be fatally overloaded; in the second position, because of the overprotection of e4, it can not. The added extra resource is that in the second position after <1...Rxc4> the <2.dxc4! Rxc4 3.Nxc4 Qe4 4.Ne3...> is possible (and winning).

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Nimzo is talking about all this high
fallutin' overprotection stuff.

A guy like Capablanca approaches the
two positions you mentioned without
any preconcieved notions. His fast
"sight of the board" always him to
quickly calculate the outcome of both
positions. He makes the right move,
and it's end of story.

IF you happen to be called J.R. Capablanca.

<His fast "sight of the board" always him to quickly calculate the outcome of both positions. He makes the right move, and it's end of story. > This is very true. But it should not be interpretted automatically as Capa being a calculating machine as, say, Korchnoi. From what I have been able to piece together from writings of Kotov, Botvinnik, Bronstein -- and from Capa's "Last Lectures" -- Capablanca actually had a peculiar and specific style of thinking, quite unique till his time (with a possible exception of Paul Morphy). Capa thought about positions in structural "schemes". (That is the term Aagaard uses.) That is what helped Capa deeply assess positions in such lightning speeds. He broke down the problem into two parts, and he was brilliant in solving both. First he quickly assessed the structure of the position and determined what needs to be done : he set up a schema to achieve. Second he used his phenomenal tactical vision to determine the sequence of moves, sometimes a combination but usually a maneuver, that quickly got the position into his desired schema. Then repeat, and again.

Capa's structural understanding of the game was head and shoulders above most of his era. But, I do believe, this understanding was also condensed into a type of his system. It is from this that he readily conjured up his schemas. See, at their native levels, the systems of Tarrasch, Nimzo, or Capablaca are a form of some high level understanding of what what chess is about. This then gets translated via a trail of levels of doctrine, high-level policy, concrete policy, rules of thumb, strategy, down to concrete tactics and maneuvers.

Not all players work like that. Some function mostly at the concrete levels (Korchnoi, Duras) some are concrete planners and strategists (Botvinnik, Rubinstein), some work from the rules of thumb, and some are philosophers of the higher ralms.

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What I see people objecting w.r. to Tarrasch and Nimzo is that, for us, they boiled their high level understanding of the game into a bunch of rules of thumb. These rules were designed to give us, their readers, a head start. But we now take these rules as gospel of proper play and, unlike their originators, we do not understand the source of these rules and therefore we do readily know when we can or even need to break them.

Incidentally, Capa's system never realy get boiled down to a set of rules of thumb, as much as Nimzo's system or Tarrasch's system had, because Capa was not the teacher they were.

Very macho sounding!

The idea that chess is all about calculation has become increasingly popular recently, partly, I think, as a result of Hydra et al.

For argument’s sake let’s say that Adams achieved a strength of play roughly 500 ELO points lower than Hydra (surely an exaggeration). He did this calculating a maximum of 5 positions a second. Hydra does several tens of millions.

So his efficiency in assessing positions, choosing candidate moves and “pruning the tree of analysis” must be literally hundreds of thousands of times better (Kotov’s book only really addresses (c)- all he says about candidates is “look at as many as possible”).

Where does this come from? Positional understanding, logic and reasoning.

I am still not sure what you are illustrating is overprotection per se. As I understand it, Nimzowitsch believed in overprotecting key strategic points before the opposition had made any specific tactical threats, with the payoff being (i) the enemy’s future plans would be frustrated and (ii) the pieces dedicated to overprotection “would find themselves well-placed in every respect.” However, in your positions white has clear and glaring weaknesses on the light-squared diagonals around his king. Black has occupied one of those diagonals with his bishop and threatens to occupy the other by moving his queen to e4. Also, in your second diagram e4 might be formally overprotected, but because of the possiblity of …Rxc4 it is really only protected once, by the knight. In short, black has an immediate, dangerous tactical threat. If I had this position I would think of it, not in terms of overprotection, but in terms of defense of the k-side light squares. (Or even simpler: how do I avoid getting mated?)

To illustrate, let’s go back a half move from your diagram, put the white knight on b1 and rook on a1, and make it white’s turn to move. (I realize you did not devise your two positions—which must have been a huge amount of work—to be analyzed in this way. But surely the true test of a doctrine like overprotection is how it helps us to plan in a game.)

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If I had to choose between 1 Nd2 and 1 Na3, I would certainly prefer the former, with the idea of trying to cover the weak squares around the king, in particular f3 and e4. But note that I could ignore overprotection altogether and simply play 1 Rxc7, removing the threat to destroy the guard of e4. What I would probably do in the diagrammed position is play 1 Nc3, guarding e4, developing a piece, clearing the back rank and hoping to follow up with perhaps Rh4 and Qh5. Note that none of these thoughts are based on overprotection.