The Static Centre: what did they mean?

Helloo future grandmasters

Regarding this quote:

ICS-centre-intro wrote:Static centre – there are 2 half-open files or only 1 open file in the extended centre and the pawns forms chains, but without blocking each other.

What do they mean with "but without blocking each other" & "extended centre"?
I observe the first game "Damljanovic, Branko vs Marjanovic, Slavoljub" and The c&d-pawns are blocking each other, the e-file is entirely open. So I'm thinking:
1. what is an "extended centre" to begin with? Surely this must be a typo as the e-file is not "extended centre", but the actual centre. To me the extended centre would be the c&f-center squares.

2. So pawns c & d are blockading each other, therefore this is not the case this definition means. So what does it mean?

Extended centre includes the c & f files.

I think they were fast and loose with the original definition, and mean by the chain comment that the entire chain is blocked, not just the centre/extended centre. The example states:

In the positions characterized by a blocked
pawn structure in the center and the presence
of one open or half-open file ...

so the position qualifies as a static centre. The chain is not blocked because b3 and b4 breaks could happen. Just a guess.

Honestly, when I look at a position and the centre in my correspondence games, I go right down the list and discount them in order. What is left are my choices.

a) Closed centre – the entire centre is blocked by chains of pawns of the 2 players
and the opponent chains block each other. - NO

b) Open centre – there are 2 completely open files in the extended centre (for
example, when both c- and d- files are open, even if there are pawns on the e-file) - NO
c) Static centre – there are 2 half-open files or only 1 open file in the extended centre
and the pawns forms chains, but without blocking each other. - MAYBE
d) Mobile centre – when a player has a mobile pawn formation in the centre or in the
extended centre, while the other player has no pawns to counter it (rarely met). - NO
e) Dynamic centre – this is the most often met type of centre. It is characterized by a
still undefined pawn structure in the centre and it can derive in any other type. - NO

So, by process of elimination, it can only be a static centre.

Ah yes, thank you.
What is the centre in the image below? Should it be a dynamic then as it has only 1 half-open centre file, but the c & e-file could be played by white, thus potentially re-defining the centre. Is my assessment correct?

Using my magic "formula":

a) Closed centre – the entire centre is blocked by chains of pawns of the 2 players
and the opponent chains block each other. - NO
b) Open centre – there are 2 completely open files in the extended centre (for
example, when both c- and d- files are open, even if there are pawns on the e-file) - NO
c) Static centre – there are 2 half-open files or only 1 open file in the extended centre
and the pawns forms chains, but without blocking each other. - NO
d) Mobile centre – when a player has a mobile pawn formation in the centre or in the
extended centre, while the other player has no pawns to counter it (rarely met). - NO
e) Dynamic centre – this is the most often met type of centre. It is characterized by a
still undefined pawn structure in the centre and it can derive in any other type. - MAYBE

I think it would be considered "dynamic" by excluding the other types.  But that example is a very odd formation. I've never seen that before.

It's really about understanding how to direct your play through the various centre types.

This is from the Ragozin (QGD). Black played the less played - but strong - ...Bf5. Here black made a less fortunate decision to play ...Nc6, nevertheless it's hard to exploit it. White traded off the queens.

That's the background of it. But I wondered what play this kind of a structure would dictate.

Valmont wrote:Ah yes, thank you.
What is the centre in the image below? Should it be a dynamic then as it has only 1 half-open centre file, but the c & e-file could be played by white, thus potentially re-defining the centre. Is my assessment correct?

I have a faint recollection that the definition was somewhat different in one of the example games in the course than that given in the front matter to the lesson. (edit: I see it was in the first example game as mentioned).

The giveaway for the diagramed position is the pawn ram which means it is not a dynamic centre.

Marovic in his book "Dynamic Pawn Play in Chess" observes that this type of centre often mutates to others, mostly the dynamic centre which only adds to the confusion...

I remember something vaguely about a pawn ram, but where was it exactly. I can't find it now.

Valmont wrote:I remember something vaguely about a pawn ram, but where was it exactly. I can't find it now.

I first leaned about it 50+ years ago in a book, Pawn Chess by Hans Kmoch. Odd book with many strange terms like Rams and Levers, but very helpful for beginners. It helped me gain my first tournament trophy.

It didn't get as much respect as some of the other classics like My System, but in my opinion it should be near the top of the lists of must read chess books for anyone starting out in chess.

You can google the author and title and find a lot of material online.

Oh OK, I also have a shit ton of PDF's , I'll check it later.
Can you quickly define what a pawn ram is again?

Valmont wrote:Oh OK, I also have a shit ton of PDF's , I'll check it later.
Can you quickly define what a pawn ram is again?

It is a term for when the advance of a pawn is blocked by an enemy pawn, i.e. d4 vs d5 is a Ram.

There is a summary of his terminology at the link https://www.chessprogramming.org/Hans_Kmoch