Thursday, December 29, 2005

Understanding and applying the Tsuke Nobi Joseki

After B-Q18, W-N17 becomes a vital defense point.
W-R14 exposed this point to attack.

As much as I have received counsel to not bother with josekis at this early a level, I have continued to study them (becuase it's fun) and the one I am focused on these days is the tsuke nobi. I've been opting for high(er) handicap games in order to test my understanding.

In my second game of the day, White played the joseki out perfectly up to move number 7. With the right tactical skill, an invasion around the vicinity of Q14 to R13 is still possible but, in this particular handicap position, it would serve to strengthen Black's position in the lower right. The corner will live easily. A tenuki is generally the next move after B-R10.

Instead, White opted to push and hane with P16 and Q15 (moves which Yoshio Ishida calls "reckless"). Black Q14 and Q18 ensure the defensibility of the corner and certainty of White dying if the corner is sought and if the vital points are understood. After Black Q18, White must protect with N17 as it becomes a weak point.

White opted instead to play R14, allowing Black to make the cutting move.

The game as it progressed to move 34.
I wonder if I could have kept White's group smaller?

As the game progressed, the O17 group died, Black lived in the corner and got outside influence after containing White.

It might have been possible for Black to better contain White to the side but I was trying to keep it simple for myself. If anyone has some ideas, I'd really like to hear them.

My understanding of this joseki is based on Ishida's writings from 1977. There's always the possibility that the Koreans may have discovered new countermeasures in their own jeong-seok (정석). Among the current crop of English Go bloggers, Mr. Ooijer would likely be the most knowledgable of Korean improvements to joseki. It would be interesting to see if something new exists.


At 6:11 PM, December 29, 2005, Anonymous Shawn McHorse said...

Black 14 (at Q18) looks too passive. It should probably have been at R14 instead to keep the capturing race going. Black should have the advantage in that fight.

At 6:30 PM, December 29, 2005, Blogger ChiyoDad said...

Hello Shawn!

Thanks, BTW, for the plug on your page!

Ishida explained that Black 14 is essential after the push and cut (sequence to 13) to ensure the survivability of the corner. Black retains sente because of the threat to N17.

After White plays N17 to defend his position, Black plays R14 and any further encroachment by White into the corner will result in the capture of all stones this early in the game. In the optimal shapes that could emerge, there will always be two vital points for Black to play in order to kill.

An encroachment could survive if White has enough ko threats.

Of course, this is all based on material that's 28 years old. I've only studied a third of the variations of this joseki and haven't looked at the more complicated branches yet.

At 8:21 AM, December 30, 2005, Blogger ChiyoDad said...

After replaying the game, it looks like my 28th move should have been a hane at R12. The health of black's groups seem to be more robust than I thought. Cuts by White could easily be dealt with.


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