Well, I'm tired. I cannot remember which is the variation to prevent the 20.t17 attack against the Achille... :-(
There should be one isn't it ?
On
2011-11-05 at 13:48,
Alan Hensel
said:
It's not an Achilles, because of the q20 peg. It's a standard flanking peg (u19) on an 0-2 opposition (q18:q20). I believe the first response you should consider to the tilt crossing is |21.v17. A more common, but generally worse line for White, is |21.s1922.s2123.v2124.t1925.v1726.s17, but by the time the v17 peg goes down, Black has been given the opportunity to place a linked s17 peg, and that is almost certainly worse for White. I see no risk to placing v17 first, in general, so that is what I recommend. I think it looks good here, but I have not spent much time on the variations.
Sorry, I misspoke, it's the q18 peg that distinguishes this pattern from the Achilles, not q20. By "Achilles", I mean something like this: |8.o199.s18 - it's a series of 1-4 blocks inside the lines toward a corner. The presence of your own peg 1-4 away changes things.
When you say "both |21.v17 and |21.s19 come to the same", I think you miss that the link on s17 could be important. For example, |21.v1722.s2123.v2124.s17 and then 25.r16.
|30.t12 31.v15 32.u15
|30.t12 31.w14 32.v11 33.t16 34.s15 35.s17 36.s19 37.s20 38.r21 39.p22 40.s23
The final position is tricky:
|32.s15 33.w14 34.s11 35.t11 36.r9 37.r12 38.q12 39.p13 40.o13 41.n14 42.m14 and Black wins
|32.s15 33.w14 34.s11 35.t12 36.u10 and Black wins
|32.s15 33.w14 34.s11 35.u10 36.u8 37.v8 38.t10 39.t12 40.t13 41.t11 should work for White, also
|32.s15 33.w14 34.s11 35.u10 36.u8 37.v8 38.t10 39.t11 40.s12 41.t12
27.u18 28.s16 29.s13 30.r14 31.u12 32.s12 33.s11
26.v18 27.w18 28.u14 29.s18 30.s17 31.t16 32.t15
Well, I'm tired. I cannot remember which is the variation to prevent the 20.t17 attack against the Achille... :-(
There should be one isn't it ?
However, it seems that both |21.v17 and |21.s19 come to the same : |21.v17 22.s21 23.v21 24.s17
Btw, I cannot see the difference with a "standard" Achille such as |8.o19 9.o17 10.m18 11.q18 12.q20 13.u19
When you say "both |21.v17 and |21.s19 come to the same", I think you miss that the link on s17 could be important. For example, |21.v17 22.s21 23.v21 24.s17 and then 25.r16.
|27.u18 28.w21
I was comparing
|21.s19 22.s21 23.v21 24.t19 25.v17 26.s17, then 27.u15
and
|21.v17 22.s21 23.v21 24.s17. if 25.r16 then 26.t19 27.u15
I agree that the later is better for white.
@Mirko : Sorry for my stupid comment...