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Topic: Advanced tactic: Double-blocking trias
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karlw

Posts: 946
Registered: Mar 7, 2006
From: Eugene, Oregon
Age: 32
Advanced tactic: Double-blocking trias
Posted: Oct 6, 2008, 5:04 AM

Double-blocking trias: Blocking an opponent's tria on one side, then blocking the other side before he extends.

-This tactic is very strong when executed correctly because a tria is useful only in that it is a heartbeat away from becoming a tessera, and you can attack the keystone* that the tessera creates.
-Double-blocking sacrifices initiative to prevent the future creation of a tessera, thereby neutralizing the tria.
-It is usually best to double-block when doing so gives you a solid structure and nullifies the opponent's offense.

*Keystone: a stone which blocks one end of a tessera, and therefore must be immediately replaced if captured, sacrificing initiative

Here is a game that perfectly illustrates this tactic twice:



Here are the double-blocks:


K10,N8,K7,N10,H9,K9,J8,G10,N7,L6


and:


K10,N8,K7,N10,H9,K9,J8,G10,N7,L6,M7,L7,L5,O7,L8,L6,M9,J6


Since his trias are double-blocked, his offense is critically weakened, and the strength of my corner shape is enough for me to attack his pairs and win on caps.

Discuss!

It's no use going back to yesterday, because I was a different person then.


redsky_iv

Posts: 107
Registered: Feb 17, 2008
From: Edge of Space
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Re: Advanced tactic: Double-blocking trias
Posted: Oct 6, 2008, 5:13 AM

This dummy shoulda played k5. I sure hope he doesn't breed or have an important job or anything.

karlw

Posts: 946
Registered: Mar 7, 2006
From: Eugene, Oregon
Age: 32
Re: Advanced tactic: Double-blocking trias
Posted: Oct 6, 2008, 10:09 AM

do you mean 9 K5? If so:

9 K5 M9
10 O11 M9
11 L10 L9
12 N9 P10

is a win for black. You can try varying the capture time and which side to block, but it all ends up the same in the end.

It's no use going back to yesterday, because I was a different person then.
redsky_iv

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Re: Advanced tactic: Double-blocking trias
Posted: Oct 6, 2008, 6:37 PM

Most of the time I think that the double blocked tria is a result of an error on the part of white, and not so much the ingenuity of black......of course black capitalizing on the error is the pivot and in this case helped win the game.......basically its the other side of the coin to what has been discussed in other threads regarding extending a blocked 3 too early in order to make a 4.......good topics for advancing ones game, but balance is the key (as demonstrated in this game) and too much emphasis on either approach will leave a player vulnerable.

zoeyk

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From: San Francisco
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Re: Advanced tactic: Double-blocking trias
Posted: Oct 6, 2008, 8:45 PM

i liked what karl is saying here,..there is a point to what red is saying too as far as over emphasizing either way i guess,...and i question whites 3rd and its 5th.
but,..given how white chose to go, ide say i think black played it well. and the double blocking was good in this game.
also i like that karl explained the keystone definition.
and ide like to see more posts like this. red perhaps you have a post to share with us about a game or pente theory or basic principle errr something, thanks.

~zoeyk

Scire hostis animum - Intelligere ludum - Nosce te ipsum - Prima moventur conciliat - Nolite errare
redsky_iv

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Re: Advanced tactic: Double-blocking trias
Posted: Oct 6, 2008, 8:59 PM

LOL Z....I think I prolly share a bit too much for the most part as a rule, but I'll try to wrap my mind around something intelligent for once and post it as soon as the light-bulb starts to flicker And yes black definitely gave me a good ***-kicking here by double blocking after I should have extended......the point I was trying to make without descrediting karl's point is that its an artifact of the place I'm at in my nubile career that I've embraced the notion of holding off on an extension so much that it makes me vulnerable at times.....time to swing a bit more toward the middle to galvanize that part of my game

zoeyk

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Re: Advanced tactic: Double-blocking trias
Posted: Oct 6, 2008, 9:13 PM

well lets create a basic rule of extension. well i think its already been said long ago. don't extend unless you need to. is the rule. to clarify thou, you may not feel u need to persay but, if the opponent double blocks you and this puts you into a bad position then i guess you needed to extend thus the same rule still stands. i tell you thou,.. there are games where if my opponent double blocks me ill have an advantage, so being double blocked alone does not warrant the need to always extend.

if u need to then do it,...if you don't then don't,..the same basic rule as always. but now most people think of the rule in terms of saving the extension for personal use later or for keeping a blocking stone off the end that can either become a capping stone in a cap chain or can just become a piece of connectivity to other stones of conductivity. but now we add in the double block threat as an addition chain of thought when deciding the age old question,..to extend or not to extend.

Scire hostis animum - Intelligere ludum - Nosce te ipsum - Prima moventur conciliat - Nolite errare
zoeyk

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Re: Advanced tactic: Double-blocking trias
Posted: Oct 6, 2008, 9:16 PM

oh and,.. lets not forget the other one,...richard's "Soft Block" as he calls it.

Soft block : to block one space beyond the end of a tres or pair in such a way that denies one?s opponent an extension into sente on one end.

Scire hostis animum - Intelligere ludum - Nosce te ipsum - Prima moventur conciliat - Nolite errare
karlw

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From: Eugene, Oregon
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Re: Advanced tactic: Double-blocking trias
Posted: Oct 7, 2008, 1:33 AM

To redsky:

Yes, deciding whether and when to extend is a very complex part of pente theory. Extending right away eliminates the option of stretching (ooo+o), and provides the opponent with an extra stone which he can use offensively. In the case of this game, extending might've helped in that it would've prevented me from double-blocking, but it would've calcified your structure and given me more free stones to work with. Tough call.

I have used double-blocking many times in the past against players even stronger than you, and I believe it can be used proactively as well as in response to opponent's errors, for the very reason that (as you pointed out) extending right away is almost always a mistake, and as such you always have time to double-block if the situation warrants it.

To zoey:

soft-blocking a blocked 3 is an excellent alternative to double-blocking if it provides you with a better structure. However it is weaker defensively in that your opponent can still extend (without sente, importantly) and create a keystone.

Keystones

Keystones are important because since they block a tessera, they are a huge vulnerablity if they ever become part of a pair. This matters because oftentimes you want to make a tria to continue your attack, but doing so pairs one of your tria-stones with the keystone. The opponent can ignore the tria and instead attack the keystone pair, because he can capture through your open 4 and free his own 4 simultaneously. This is one of the most important and often-used tactics in pente (the hammer is a classic example). Also if two keystones are ever paired, you're in trouble. Capture them and it's game over.

It's no use going back to yesterday, because I was a different person then.
dweebo

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Re: Advanced tactic: Double-blocking trias
Posted: Oct 7, 2008, 7:48 PM

> soft-blocking a blocked 3 is an excellent alternative
> to double-blocking if it provides you with a better
> structure. However it is weaker defensively in that
> your opponent can still extend (without sente,
> importantly) and create a keystone.

Seems to me that even with double-blocking, the opponent can still create a keystone by playing on either side of the block (without sente of course). That doesn't happen very often but sometimes I look for it.

-dweebo

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zoeyk

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Re: Advanced tactic: Double-blocking trias
Posted: Oct 7, 2008, 9:31 PM

yes thats true,..it can happen, and its rare

Scire hostis animum - Intelligere ludum - Nosce te ipsum - Prima moventur conciliat - Nolite errare
up2ng

Posts: 542
Registered: May 9, 2002
From: Northeast USA
Age: 38
Re: Advanced tactic: Double-blocking trias
Posted: Oct 9, 2008, 1:31 AM

Great thread idea here. This is one of those tactics that isn't talked about a lot, and doesn't come into play a lot, but does occasionally play a key role in a tight game. It's something that neither player often even looks for until they've reached a pretty high skill level, and like has already been mentioned, it's something white often does not consider when trying to lay out an attack and can end up being quite a problem.

I've actually used this pretty recently myself against very strong opponents -- if I get a chance perhaps I'll look through some of my games and post an example.

This game posted here is interesting because it comes up a couple of times. In this case though, I'm not convinced that it does enough to secure a win since white probably could have eeked out a win with 10. H8. Of course, it's pretty ugly though, which is certainly one of the goals for black.

karlw

Posts: 946
Registered: Mar 7, 2006
From: Eugene, Oregon
Age: 32
Re: Advanced tactic: Double-blocking trias
Posted: Oct 9, 2008, 3:58 AM

> white probably could have eeked (sic) out a win with 10. H8.

I disagree. Show me how please (assume I answer G8).

It's no use going back to yesterday, because I was a different person then.
up2ng

Posts: 542
Registered: May 9, 2002
From: Northeast USA
Age: 38
Re: Advanced tactic: Double-blocking trias
Posted: Oct 9, 2008, 10:44 PM

Oops, you're right. Disregard.

sjustice

Posts: 72
Registered: Dec 16, 2001
From: pensacola
Age: 40
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Re: Advanced tactic: Double-blocking trias
Posted: Oct 11, 2008, 5:21 AM

9. H8 instead of 9. M9 looks good to me.

Initiative is what it is all about. Blocking a tria can be effective given the situation. Obviously, not extending prematurely is generally the correct play, but I have found myself realizing too late sometimes that I should have extended. Getting blocked and not having the initiative that you thought you had can be difficult.

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