[Retros] Type D, new length record
Mario Richter
mri_two at t-online.de
Wed Apr 25 10:47:56 EDT 2007
Dear retro fans,
as already announced by Alain Brobecker in a recent
posting:
> And Bernd also promises a D23/13!!!
Bernd Schwarzkopf has improved again his own length
record for unique retractions in a Type D problem.
In fact, in his 23 pieces position, the last 14
single moves are uniquely determined:
Bernd Schwarzkopf
7B/1p1p2p1/6p1/8/5P2/3PPrP1/P1Prqppb/K1kBBB1b
11+12=23 Last 14 single moves, Duplex.
If White starts retracting, the last 15 single moves
are determined:
-1.h7-h8=B Bg1-h2 -2.h6-h7 Bh2-g1 -3.h5-h6 Bg1-h2
-4.h4-h5 Bh2-g1 -5.h3-h4 Bg1-h2 -6.h2-h3 h3xNg2
-7.Nh4-g2 Bg2-h1 -8. Nf5-h4
If Black starts retracting, the last 14 single moves
are determined:
-1. .. Bg1-h2 -2.h7-h8=B Bh2-g1 -3.h6-h7 Bg1-h2
-4.h5-h6 Bh2-g1 -5.h4-h5 Bg1-h2 -6.h2-h4 h3xNg2
-7.Nh4-g2 Bg2-h1 -8.Nf5-h4
But that's still not the absolute length record for
a Type D problem.
Bernd was able to produce a position in which the
last 15 single moves are uniquely determined:
Bernd Schwarzkopf
7B/1p1p1pp1/8/8/4PP2/1PPPkrP1/bPKNrppb/NQn1qb2
12+14 Last 15 single moves, Duplex.
If White starts retracting, the last 16 single moves
are determined:
-1.h7-h8=B Bg1-h2 -2.h6-h7 Bh2-g1 -3.h5-h6 Bg1-h2
-4.h4-h5 Bh2-g1 -5.h3-h4 Bg1-h2 -6.h2-h3 h3xBg2
-7.Bh1-g2 h4-h3 -8.Bg2-h1 h5-h4
If Black starts retracting, the last 15 single moves
are determined:
-1. .. Bg1-h2 -2.h7-h8=B Bh2-g1 -3.h6-h7 Bg1-h2
-4.h5-h6 Bh2-g1 -5.h4-h5 Bg1-h2 -6.h2-h4 h3xBg2
-7.Bh1-g2 h4-h3 -8.Bg2-h1 h5-h4
Regards,
mario
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