Snow White In The Dark Woods / Solution

Even if Black starts, Snowwhite can escape to one of the marked points.

[Diagram]
Snow White's escape (1)  

Black is off to a good start with B1, but W2 is a clever response making miai.

Black 3 blocks one way, but W4 just heads for the opposite direction. B5 is forced and White makes miai again with W6. Rest of sequence is forced.

--Arno


Well, apart from the fact that I think black would be better off starting on one of the points where W6 is in the diagram, you appear to be right.

-- uXs


JamesA: Doesn't Snow White take less casualties this way (I think it looks simpler as well... just personal preference!)

[Diagram]
Less casualties...(2)  
[Diagram]
(3) just for clarity: after W10...  

tderz: just for clarity: if Black blocks after W10,
White can play W2 (or a+c or b+c etc.).

[Diagram]
Ladder  

Bill: Or White has a ladder. ;-)

[Diagram]
(4) ponnuki  

tderz: if Black blocks at the inside, White gets a ponnuki.

[Diagram]
(5) Black plays on ...  

tderz: Black better prolongs the game ...
[50] B3 and a are not equivalent. Black a might be safer.
(see continuation below)

[Diagram]
(6) Black plays on ...  

tderz: Black better prolongs the game ...

[Diagram]
(7) Black plays on ...  

tderz: ... and now?
What is the real continuation?
2 years ago, I posed this problem as a miai exercise for our beginners in the club up to 15 kyu at that time. I created a PDF which I hope to link somewhat later here, and remember that White has to be careful!. This doubling of moves - say a super-nobi was not equal to the strategy where white constantly makes miai of the mirror symmetry points, i.e. constantly spreads in different directions (e.g. W8 in dia (6) above) and puts her stones on the junctions between the bamboos (i.e. the W2 here and W2, W6 in diagram (1) but not W4, W8, W10, but then always! uXs pointed that out already).

This would work on an indefinite board, but this doubling strategy here would not! (I still might be mistaken).
Perhaps I have created an SGF of my former trials and can retrieve it.

[Diagram]
(8) Black plays on ...  

JoelR: I take Bill's ladder to be the definitive answer to "what happens if Black blocks on the 4th line". But it's worth pointing out that Black has to be careful in other ways: The bamboo joint may be short of liberties.

tderz: Good point indeed. This diagram shows that B5 (as B3, B7 and B9) in dia (2) where mistakes, because one does not need to take liberties of a group which you would like to contain. (Because it also costs your own liberties).

Black B5 could be played at a (dia (2)), for the other moves, the junctions b, c and d might be more advisable as addressed above.
White W8 here would also not work if Black had played his B3 in dia. [50] above on the place of the right W8.


Case I, Black starts

[Diagram]
Systematic approach (1) Case I, Black starts  

tderz: I would like to try a Systematic approach here,
Case I: Black starts, B1.
Contrary to the initial remark of s.o. above, it might make a difference.

[Diagram]
Systematic approach (2), moves 11-end.  

tderz: White did not succeed (reach the 4th line with the center chain)

Case II: White starts.

[Diagram]
(3) Case II: White starts, B1 = tenuki  

tderz: I display it as B1=tenuki, for better detection of any difference. The white numbers the remain the same (and I can copy the diagram :-) ).

[Diagram]
(4) Case II: White starts, moves 11-  

tderz: seems no difference, because capturing does not help White,
but the left W8 in dia (3) is not placed optimal, it is not forming miai with the center stone, only for connection with the left W2.

Playing a ladder, white can win with a-a(cf. below [8].

Ed?: White's moves at W4 are unnecessary, this allows black to kill with B5 at W6 Playing W2 W2 at 'b' and B3 sets up a ladder immediately.

[Diagram]
(5) Case II: White starts, B1 = tenuki  

tderz: Hence, the quest for a solution continues...

[Diagram]
(6) Case II: White starts, B1 = tenuki  

tderz:

Ed?: Playing W8 W8 at 'a' and to the right of 'a' sets up a ladder immediately.

[Diagram]
(7) Case II: White starts, B1 = tenuki  

tderz: this is too fast, too easy ...

[Diagram]
(7b) Case II: White starts, B1 = tenuki  

tderz:

[Diagram]
(8) Case II: White starts, B1 = tenuki  

tderz: Black connects at a, White lost.
If the problem is constructed in such a way that the edge is at e, White might succeed (Black B9 could be captured).

[Diagram]
(8a) Case II: White starts, B1 = tenuki  

tderz: Playing a ladder seems possible ...

[Diagram]
(8b) the ladder  

tderz: [8] Playing a ladder, white wins.


BillSpight: I think that both James' and uXs' ideas are interesting. :-)

[Diagram]
Snow White's escape (iii)  

Snow White In The Dark Woods / Solution last edited by 137.222.14.101 on May 12, 2007 - 02:22
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