Shape problems

illluck · Post by **illluck** » Thu Jun 28, 2012 8:11 am

Bill Spight · Post by **Bill Spight** » Thu Apr 30, 2015 8:49 am

Oops! This seemed to have slipped my mind. :oops:

Illluck got it right.

The answer:

Click Here To Show Diagram Code: [go]$$W White to play $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . X . . . . . . . . . . . . . | $$ | . . . O . . . X . . . . . X . . . . . | $$ | . O O O . O . . . , . . . . . X . . . | $$ | . X X O X . . . . . . . . . . . X . . | $$ | . . X X . . . . . . . . . 6 . . . . . | $$ | . . O . . . . . . . . . . 5 X . O . . | $$ | . . . X . . . . . . . . . 7 . X . . . | $$ | . . X . . . . . . . . . . . O . 8 . . | $$ | . . . , . . . . . , . . . 1 . , O . . | $$ | . . O . O . . . . . . . 4 . . . . X . | $$ | . . . . . . . . . . . . . B X X X X . | $$ | . . . . . . . . . . . . 2 O O O O X O | $$ | . . . . . . . . O . . . . . . . . O . | $$ | . . O . . . . . X . . . . 3 . X O . . | $$ | . O . O . . X X O O . . . . . , O . . | $$ | . X X O . X O O . O . . O X . X X . . | $$ | . X . X O . X O . O . . . . . . . . . | $$ | . . . . . . . . O . . . . . . . . . . | $$ ---------------------------------------[/go]

is an efficient connection with an eye towards the center, which threatens to cut off the Black stones on the right side.

The game continued as indicated.

Here is the SGF file.

Bill Spight · Post by **Bill Spight** » Fri May 08, 2015 9:43 am

Shape problem #4:

Click Here To Show Diagram Code: [go]$$Bc Black to play $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X X . . | $$ | . . . . . . . . . . . . . . O O X . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

From the Okigo Jizai, by Hattori Inshuku.

Enjoy!

skydyr · Post by **skydyr** » Fri May 08, 2015 11:22 am

Bonobo · Post by **Bonobo** » Fri May 08, 2015 11:41 am

Bki · Post by **Bki** » Fri May 08, 2015 2:25 pm

Bonobo wrote:
My immediate impulse: cut at Q12 — b/c W can’t get that one, and any ladder is in B’s favour (I think)

As for my guess...

mitsun · Post by **mitsun** » Fri May 08, 2015 3:20 pm

Bonobo wrote:
My immediate impulse: cut at Q12 — b/c W can’t get that one, and any ladder is in B’s favour (I think)

The cutting stone cannot be captured, but W can get a ponnuki anyway, for a good result:

Click Here To Show Diagram Code: [go]$$Bc Black has no good response $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X X . . | $$ | . . . . . . . . . . . . . . O O X . . | $$ | . . . . . . . . . . . . . . 3 1 O . . | $$ | . . . . . . . . . . . . . . . 2 . . . | $$ | . . . X . . . . . X . . . . 4 X O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Bantari · Post by **Bantari** » Sat May 09, 2015 10:48 am

Bill Spight wrote:The answer:

$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . X . . X . . . . . . X . . |
$$ | . . . , . . . . . , . . . X . X . O . |
$$ | . . . O . . O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . X . . . . . , . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . . X . O . . . . . . . |
$$ | . . . . . . . O . . . . . . . O . . . |
$$ | . . . O . . . . . X . O . . . . . . . |
$$ | . . . . . . . X . . . . . . O . 4 . . |
$$ | . . . O . . . . . O O . . W . 2 X 5 . |
$$ | . . . . O X . . X X . . X . X 3 . . . |
$$ | . . . . . X . . . . . 1 . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code
[go]$$Bc Black to play $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . X . . X . . . . . . X . . | $$ | . . . , . . . . . , . . . X . X . O . | $$ | . . . O . . O . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . O . . | $$ | . . . , . . . . . X . . . . . , . . . | $$ | . . . . . . . . . . . . . . X . X . . | $$ | . . . . . . . . . X . O . . . . . . . | $$ | . . . . . . . O . . . . . . . O . . . | $$ | . . . O . . . . . X . O . . . . . . . | $$ | . . . . . . . X . . . . . . O . 4 . . | $$ | . . . O . . . . . O O . . W . 2 X 5 . | $$ | . . . . O X . . X X . . X . X 3 . . . | $$ | . . . . . X . . . . . 1 . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

protects against the push and cut and connects to the Black stones on the left.

The game:

(;SZ[19]FF[3]
PW[Go Seigen]
WR[8d]
PB[Sakata Eio]
BR[7d]
EV[Go vs. 10 High-Dan Players match sponsored by Yomiuri Shinbun]
RO[Game 10]
DT[Published 1950-03-31~04-12]
TM[10h]
KM[0]
OH[(B)-B-W]
RE[W+R]
US[GoGoD95]
;B[pd];W[dp];B[qp];W[dc];B[oq];W[de];B[jc];W[qf];B[nd];W[rd];B[qc];W[qi]
;B[gc];W[ci];B[fq];W[dn];B[iq];W[ge];B[qk];W[jp];B[jq];W[kp];B[ho];W[eq]
;B[fr];W[hm];B[jn];W[ln];B[jl];W[ll];B[jj];W[pm];B[ok];W[oo];B[mq];W[np]
;B[lr];W[pp];B[pq];W[qo];B[rp];W[pj];B[pk];W[nj];B[om];W[nl];B[nk];W[mk]
;B[qm];W[ol];B[pl];W[pn];B[ro];W[gj];B[ck];W[io];B[mm];W[ml];B[in];W[hn]
;B[lo];W[go];B[lm];W[km];B[kn];W[mn];B[hp];W[dh];B[cq];W[cp];B[cn];W[bo]
;B[cc];W[eb];B[fi];W[gi];B[cg];W[cd];B[bd];W[be];B[dm];W[en];B[bi];W[bj]
;B[cj];W[bh];B[di];W[ch];B[bk];W[ai];B[em];W[lp];B[gl];W[hl];B[fn];W[fo]
;B[gn];W[fm];B[gm];W[fl];B[gk];W[fk];B[hk];W[fj];B[bq];W[bm];B[cm];W[bn]
;B[er];W[mp];B[hj];W[dq];B[dr];W[dj];B[ed];W[fd];B[fc];W[ec];B[he];W[hf]
;B[ie];W[gd];B[hd];W[gg];B[if];W[qn];B[rn];W[rm];B[ql];W[oe];B[fp];W[bp]
;B[bl];W[dl];B[cl];W[ep];B[od];W[rc];B[rb];W[mf];B[pf];W[qb];B[pe];W[pb]
;B[ob];W[qg];B[ap];W[eo];B[ao];W[dk];B[hh];W[gh];B[mh];W[ng];B[nh];W[og]
;B[pg];W[oh];B[hg];W[gf];B[ph];W[lh];B[oj];W[oi];B[qh];W[mi];B[rh];W[sb]
;B[lj];W[mj];B[ra];W[qa];B[re];W[qe];B[rf];W[qd];B[pc];W[sa];B[rg];W[sd]
;B[lg];W[mg];B[pi];W[gb];B[hc];W[fb];B[kh];W[li];B[gp];W[al];B[le];W[lf]
;B[kg];W[me];B[md];W[ke];B[ld];W[kf];B[ak];W[am];B[ki];W[hi];B[ii];W[ja]
;B[aq];W[el];B[ha];W[la];B[ma];W[hb];B[ib];W[ia];B[kb];W[kk];B[ka];W[oa]
;B[nb];W[ik];B[ij];W[jk];B[il];W[nq];B[nr];W[nm]
)

One thing that always bothered me about this kinds of answers is: why do we assume pros are always right?

I mean, sure - they are strong, much much stronger than us... but we do not only talk about "better" move or "better" plan, we talk about "The Answer" here - the one and only correct move and plan. And it makes me wonder... would another pro come up with a different move? Or a better move? Maybe a different plan? Are there are few equivalent moves in this position, or is m2 the only, or the absolutely best, move? And how dowe know it?

Would "God" play this move?
Or would She even get into this position to begin with? And if not, what does it tell us about the judgement of this particular pro?

And I don't necessarily mean this particular problem, I am really not strong enough to judge.
Just thinking out loud here...

PS>
I think it would help if we had some kind of a consesus here... like several pros analysing this position and all uneqivocally agreeing that m2 is the best move. Otherwise we just have one pro who has played one move... what if it was a mistake or a slack move? Pros make those as well...

oren · Post by **oren** » Sat May 09, 2015 11:06 am

Bantari wrote:]
I think it would help if we had some kind of a consesus here... like several pros analysing this position and all uneqivocally agreeing that m2 is the best move. Otherwise we just have one pro who has played one move... what if it was a mistake or a slack move? Pros make those as well...

That's why I like commentary, since often there are plenty of moves that look fine to pros and will be mentioned.

Also one book which gives three pros independently an opening position and asking how they would play. All three get fairly different games quickly and some dismiss openings another pro had picked.

Bill Spight · Post by **Bill Spight** » Sat May 09, 2015 11:18 am

Bantari wrote:
Bill Spight wrote:The answer:

$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . O . . X . . X . . . . . . X . . |
$$ | . . . , . . . . . , . . . X . X . O . |
$$ | . . . O . . O . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . O . . . . . . . . . . . . . O . . |
$$ | . . . , . . . . . X . . . . . , . . . |
$$ | . . . . . . . . . . . . . . X . X . . |
$$ | . . . . . . . . . X . O . . . . . . . |
$$ | . . . . . . . O . . . . . . . O . . . |
$$ | . . . O . . . . . X . O . . . . . . . |
$$ | . . . . . . . X . . . . . . O . 4 . . |
$$ | . . . O . . . . . O O . . W . 2 X 5 . |
$$ | . . . . O X . . X X . . X . X 3 . . . |
$$ | . . . . . X . . . . . 1 . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code
[go]$$Bc Black to play $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . O . . X . . X . . . . . . X . . | $$ | . . . , . . . . . , . . . X . X . O . | $$ | . . . O . . O . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . O . . . . . . . . . . . . . O . . | $$ | . . . , . . . . . X . . . . . , . . . | $$ | . . . . . . . . . . . . . . X . X . . | $$ | . . . . . . . . . X . O . . . . . . . | $$ | . . . . . . . O . . . . . . . O . . . | $$ | . . . O . . . . . X . O . . . . . . . | $$ | . . . . . . . X . . . . . . O . 4 . . | $$ | . . . O . . . . . O O . . W . 2 X 5 . | $$ | . . . . O X . . X X . . X . X 3 . . . | $$ | . . . . . X . . . . . 1 . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

protects against the push and cut and connects to the Black stones on the left.

The game:

(;SZ[19]FF[3]
PW[Go Seigen]
WR[8d]
PB[Sakata Eio]
BR[7d]
EV[Go vs. 10 High-Dan Players match sponsored by Yomiuri Shinbun]
RO[Game 10]
DT[Published 1950-03-31~04-12]
TM[10h]
KM[0]
OH[(B)-B-W]
RE[W+R]
US[GoGoD95]
;B[pd];W[dp];B[qp];W[dc];B[oq];W[de];B[jc];W[qf];B[nd];W[rd];B[qc];W[qi]
;B[gc];W[ci];B[fq];W[dn];B[iq];W[ge];B[qk];W[jp];B[jq];W[kp];B[ho];W[eq]
;B[fr];W[hm];B[jn];W[ln];B[jl];W[ll];B[jj];W[pm];B[ok];W[oo];B[mq];W[np]
;B[lr];W[pp];B[pq];W[qo];B[rp];W[pj];B[pk];W[nj];B[om];W[nl];B[nk];W[mk]
;B[qm];W[ol];B[pl];W[pn];B[ro];W[gj];B[ck];W[io];B[mm];W[ml];B[in];W[hn]
;B[lo];W[go];B[lm];W[km];B[kn];W[mn];B[hp];W[dh];B[cq];W[cp];B[cn];W[bo]
;B[cc];W[eb];B[fi];W[gi];B[cg];W[cd];B[bd];W[be];B[dm];W[en];B[bi];W[bj]
;B[cj];W[bh];B[di];W[ch];B[bk];W[ai];B[em];W[lp];B[gl];W[hl];B[fn];W[fo]
;B[gn];W[fm];B[gm];W[fl];B[gk];W[fk];B[hk];W[fj];B[bq];W[bm];B[cm];W[bn]
;B[er];W[mp];B[hj];W[dq];B[dr];W[dj];B[ed];W[fd];B[fc];W[ec];B[he];W[hf]
;B[ie];W[gd];B[hd];W[gg];B[if];W[qn];B[rn];W[rm];B[ql];W[oe];B[fp];W[bp]
;B[bl];W[dl];B[cl];W[ep];B[od];W[rc];B[rb];W[mf];B[pf];W[qb];B[pe];W[pb]
;B[ob];W[qg];B[ap];W[eo];B[ao];W[dk];B[hh];W[gh];B[mh];W[ng];B[nh];W[og]
;B[pg];W[oh];B[hg];W[gf];B[ph];W[lh];B[oj];W[oi];B[qh];W[mi];B[rh];W[sb]
;B[lj];W[mj];B[ra];W[qa];B[re];W[qe];B[rf];W[qd];B[pc];W[sa];B[rg];W[sd]
;B[lg];W[mg];B[pi];W[gb];B[hc];W[fb];B[kh];W[li];B[gp];W[al];B[le];W[lf]
;B[kg];W[me];B[md];W[ke];B[ld];W[kf];B[ak];W[am];B[ki];W[hi];B[ii];W[ja]
;B[aq];W[el];B[ha];W[la];B[ma];W[hb];B[ib];W[ia];B[kb];W[kk];B[ka];W[oa]
;B[nb];W[ik];B[ij];W[jk];B[il];W[nq];B[nr];W[nm]
)

One thing that always bothered me about this kinds of answers is: why do we assume pros are always right?

I mean, sure - they are strong, much much stronger than us... but we do not only talk about "better" move or "better" plan, we talk about "The Answer" here - the one and only correct move and plan. And it makes me wonder... would another pro come up with a different move? Or a better move? Maybe a different plan? Are there are few equivalent moves in this position, or is m2 the only, or the absolutely best, move? And how dowe know it?

Would "God" play this move?
Or would She even get into this position to begin with? And if not, what does it tell us about the judgement of this particular pro?

And I don't necessarily mean this particular problem, I am really not strong enough to judge.
Just thinking out loud here...

PS>
I think it would help if we had some kind of a consesus here... like several pros analysing this position and all uneqivocally agreeing that m2 is the best move. Otherwise we just have one pro who has played one move... what if it was a mistake or a slack move? Pros make those as well...

Well, these are not best move problems, they are shape problems. What is the locally efficient play? Not, what is the best play on the board? And I think, yes, the vast majority of pro moves are locally efficient. Sometimes one sacrifices local efficiency for global purposes, but as a rule one can achieve global goals with locally efficient moves. Besides, local efficiency is easier to achieve than global correctness.

In these problems, I think that the shape play is clear. And I think that consensus among pros on shape plays is virtually 100%.

Bantari · Post by **Bantari** » Sat May 09, 2015 12:12 pm

Bill Spight wrote:Well, these are not best move problems, they are shape problems. What is the locally efficient play? Not, what is the best play on the board? And I think, yes, the vast majority of pro moves are locally efficient. Sometimes one sacrifices local efficiency for global purposes, but as a rule one can achieve global goals with locally efficient moves. Besides, local efficiency is easier to achieve than global correctness.

In these problems, I think that the shape play is clear. And I think that consensus among pros on shape plays is virtually 100%.

This makes sense, for local shape problems.
But that brings another question: is the locally most efficient shape also the globally best move?

I am sorry if I seem to be harping on that, but I just think, from the perspective of us, lowly amateurs, what do such problems teach us?

Or, better yet - I am trying to address my own insecurity when confronted with such (or any) positions. I can figure out relatively easy in many cases what is the most efficient local move, or best local shape... once somebody points out which local area they want me to focus on. But sitting at the board, trying to make the next move in a real game - this is a different animal! My main issue is not always the local shape but where to play globally. And problems like that seemingly help me, but not really.

Same goes for tsume-go, whenever I see one. But at least tsume-go usually do not make the impressions of being whole-board global problems.

So in this sense, I think what bothers/confuses me also is the context of the whole board which is given while the problem is only a local one. If the problem specified only the portion of the board which was to be considered, then none of the global-vs-local issues would arise. But since it gives the whole board, somehow, in my mind, we have to find the best move in global position, and this makes it a global problem. Which in turn makes me think: is the best local shape also the best global move? And how do we even know?

In general, I guess local problems in Go are just simpler than global ones.
And it is this globality that I struggle with the most.

I wonder if pros also have such thoughts...
I think they do.

PS>
None of that is certainly not the problem's fault, nor is it yours, Bill. Thanks for posting all that.
As I said - just thinking out loud here.

Bill Spight · Post by **Bill Spight** » Sat May 09, 2015 12:19 pm

Bantari wrote:
Bill Spight wrote:Well, these are not best move problems, they are shape problems. What is the locally efficient play? Not, what is the best play on the board? And I think, yes, the vast majority of pro moves are locally efficient. Sometimes one sacrifices local efficiency for global purposes, but as a rule one can achieve global goals with locally efficient moves. Besides, local efficiency is easier to achieve than global correctness.

In these problems, I think that the shape play is clear. And I think that consensus among pros on shape plays is virtually 100%.

This makes sense, for local shape problems.
But that brings another question: is the locally most efficient shape also the globally best move?

I am sorry if I seem to be harping on that, but I just think, from the perspective of us, lowly amateurs, what do such problems teach us?

Or, better yet - I am trying to address my own insecurity when confronted with such (or any) positions. I can figure out relatively easy in many cases what is the most efficient local move, or best local shape... once somebody points out which local area they want me to focus on.

That's why I indicated the last move for the first three problems. I think that the local area is obvious for the fourth problem, though.

lightvector · Post by **lightvector** » Sat May 09, 2015 9:25 pm

For problem 4:

Perhaps white won't respond this way, but as black, I have a nagging desire to try something silly like this. It's fun to try to settle the shape and force white around a bit.

Click Here To Show Diagram Code: [go]$$Bc Black to play $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X X . . | $$ | . . . . . . . . . . . . . . O O X . . | $$ | . . . . . . . . . . . . . . . 6 O 4 . | $$ | . . . . . . . . . . . . . . 5 2 1 3 . | $$ | . . . X . . . . . X . . . . . X O 8 . | $$ | . . . . . . . . . . . . . . . . 7 9 . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Bill Spight · Post by **Bill Spight** » Sat May 09, 2015 10:38 pm

lightvector wrote:For problem 4:

Perhaps white won't respond this way, but as black, I have a nagging desire to try something silly like this. It's fun to try to settle the shape and force white around a bit.

$$Bc Black to play
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . X X . . |
$$ | . . . . . . . . . . . . . . O O X . . |
$$ | . . . . . . . . . . . . . . . 6 O 4 . |
$$ | . . . . . . . . . . . . . . 5 2 1 3 0 |
$$ | . . . X . . . . . X . . . . . X O 8 . |
$$ | . . . . . . . . . . . . . . . . 7 9 . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . X . . . . . X . . . . . X . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------

Click Here To Show Diagram Code
[go]$$Bc Black to play $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X X . . | $$ | . . . . . . . . . . . . . . O O X . . | $$ | . . . . . . . . . . . . . . . 6 O 4 . | $$ | . . . . . . . . . . . . . . 5 2 1 3 0 | $$ | . . . X . . . . . X . . . . . X O 8 . | $$ | . . . . . . . . . . . . . . . . 7 9 . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

Interesting idea. After :w10:

captures the two Black stones, a curious feature of the resulting position is that Black does not have to protect against the atari/cut at Q-09. This amusing sequence of play shows why. :lol:

Bill Spight · Post by **Bill Spight** » Thu May 14, 2015 1:52 am

Shape play: Double peep.

Click Here To Show Diagram Code: [go]$$Bc Double peep, nobi $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X X . . | $$ | . . . . . . . . . . . . . . O O X . . | $$ | . . . . . . . . . . . . . . . a O . . | $$ | . . . . . . . . . . . . . . . 1 b . . | $$ | . . . X . . . . . X . . . . . X O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

The shape play is the nobi, :b1:

, peeping at "a" and "b". Hattori calls this a very good play. Congratulations to skydyr.

If White plays at 1 he makes good shape. :b1:

prevents that, and makes a fairly strong shape itself, with 5 dame.

To those who chose "a", Hattori calls that a good play, as well. But it is not the shape play and not as good.

Click Here To Show Diagram Code: [go]$$Bc White tesuji $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X X . . | $$ | . . . . . . . . . . . . . 5 O O X . . | $$ | . . . . . . . . . . . . . . 3 1 O . . | $$ | . . . . . . . . . . . . . . . 2 . . . | $$ | . . . X . . . . . X . . . . 4 B O . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

It allows the White tesuji which mitsun pointed out, :w4:

, putting the :bc:

stone in atari and threatening :b1:

and

. Still, Black has a ladder with :b5:

. See the SGF file below for more on this variation.

Click Here To Show Diagram Code: [go]$$Bc Empty triangle $$ --------------------------------------- $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . X X . . | $$ | . . . . . . . . . . . . . . O O X 6 . | $$ | . . . . . . . . . . . . . . . 2 O 8 . | $$ | . . . . . . . . . . . . . . . 1 3 4 7 | $$ | . . . X . . . . . X . . . . . X W 5 . | $$ | . . . . . . . . . . . . . . . . 9 . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . X . . . . . X . . . . . X . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ | . . . . . . . . . . . . . . . . . . . | $$ ---------------------------------------[/go]

In the main line White sacrifices the :wc:

stone.

forms an empty triangle, which is definitely bad shape here.

See more in the SGF file.

Life In 19x19

Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems

Re: Shape problems