RTG Problem 12 / Attempts
Mef:
I think black is dead
![[Diagram]](../../diagrams/3/ad4326c44608f8fa6756ed967abbb161.png) | First instinct |
The 1-2 point doesn't look like it will make Black 2 eyes, so lets try something else:
![[Diagram]](../../diagrams/14/942b86eac8787214a361c9a0a21fff8b.png) | Alternative A |
After Black's second eye has collapsed
![[Diagram]](../../diagrams/35/a5682ec1fedfb6a25a76579a53fab961.png) | Alternative B |
Black doesn't have enough time to save both eyes here, so white will take one either with or by playing should black neglect it.
![[Diagram]](../../diagrams/16/5693c559e18f9d08b01a4a6b7bfa3ee5.png) | One last try |
is forced, because black will immediately live by playing it.
A, B and C all look miai to keep black dead
![[Diagram]](../../diagrams/19/0ce7566037e23927f4bd82fb3b85b8b1.png) | Another chance |
Shaydwyrm: here is another interesting move I considered, but it looks like kills.
![[Diagram]](../../diagrams/19/c5fcfbeab89136f0422869f0d093ccb7.png) | Follow up |
is strong resistance, but after black is faced with a shortage of liberties.
![[Diagram]](../../diagrams/1/ff7b9ee72f617ec43d33b417fb9035b1.png) | Follow up |
Willerz: above is wrong -- this makes a and b miai -- Black a makes 2 eyes. Black b makes a seki. So Black can live. White can kill by starting at a.
![[Diagram]](../../diagrams/48/ebc849888a62aff289b8e72d582958c1.png) | White 2 at A |
Shaydwyrm: is incorrect, leaves white with no followup.
![[Diagram]](../../diagrams/12/8e7b22b93cffc044dffdae036bb71adb.png) | Not seki |
Shaydwyrm: This is not seki. White can fill black's outside liberties and then play A & B to put black in atari.
![[Diagram]](../../diagrams/20/28821b0a3e3f1a4a139b1f6aed4e8861.png) | Corrected follow-up |
Willerz: Shaydwyrm is right, however I think this makes a and b miai. So Black can live. White can kill by starting at a.
Shaydwyrm: Check the diagram labeled "White 2 at A" above for why white can't kill by starting at A.
![[Diagram]](../../diagrams/29/dfb59667f7cf3d906c1aeab9022743ca.png) | Corrected follow-up follow-up |
Shaydwyrm: Aha, but I have considered this as well! forces (in a sense, though black should really tenuki instead of all of these since he's dead), and then the situation is the same as the not-seki above.
![[Diagram]](../../diagrams/46/0231403f5c1753aba14a1c3e3b3f5c42.png) | This way? |
And if Black replies here?
WillerZ: White a and we're back to where we were just now.
![[Diagram]](../../diagrams/47/44a2e66234ad307c0d13fcf2a5fd15e4.png) | How about this? |
unkx80: Referring to Alternative A, how is this?
![[Diagram]](../../diagrams/3/f9c5c6be113bbed24e5e6563e6dba442.png) | Black has a ko? |
Shaydwyrm: Looks like black has a 2 step ko, since he needs an approach move at a. He should not play his approach move at b, since that gives white a local threat at c. White can play at , then black , white b, black c for a seki if black is komaster.[1]
![[Diagram]](../../diagrams/15/f21890019e4fb1301a7ec61e1371211e.png) | Black has a ko? |
WillerZ: Doesn't this (instead of a) give White a better result? Also, I am not sure that this is the best .
Shaydwyrm: This is not a better result, since black next plays b and has a direct ko instead of a 2 step ko. However, it seems you're right that is not the best, see below.
![[Diagram]](../../diagrams/31/cfa7408998f3594bfb3e16f25c149b8d.png) | Also ko |
Shaydwyrm: here also leads to ko, but it is direct.
[1]
![[Diagram]](../../diagrams/47/332f150ec1524faf262eac2a92f6caa5.png) | Seki? |
Nando: Shaydwyrm, this doesn't look like seki to me...
Shaydwyrm: ...you're absolutely right, I guess doesn't help black after all. at is met with at . So all the ko discussion above is merely academic, how disappointing...
unkx80: Unfortunately yeah... there is no ko here.
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"RTG Problem 12 / Attempts" at
Sensei's Library.
2004 the Authors, published under the OpenContent License V1.0.
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