[Retros] Twisted knights

[Nicolas.Dupont at math.univ-lille1.fr]

Hi Roberto,


> We worked this matter during 2006 and published in Problem Paradise a

> couple

> of PGs, not focussed on shortest length record but in the 6 knight moves

> to get the

> sibling and the complementary play strategy.

>

> I reproduce here the sending to Satoshi,

>

> ***********************************************************************************

> We made a research on the PDB and found that there are 15 PGs that show

> a mutual sibling of knights.  We made the following technical evaluation:

>

> a) The arguments of all of them to justify the siblings are a central pawn

> capture

> or check protection.

> b) In these PGs the knigths move 8-12 times. There are no antecedents in

> the PDB of

> mutual sibling using just 6 moves, wich could be named as the "standard

> mechanism" in the sense of WCCC Halkidiki 2004.

> c) The homebase position is, in some cases,  reached by the sibling side

> but

> not the oposite one.

>

> The Pgs we are sending here make the sibling in the standard way (6 moves)

> and the

> argument is the oposite side promotion instead of captures or check

> protection.

>

> -----------------------------------------------------------------------------------------------------------

> Jorge Lois & Roberto Osorio

> Argentina

> rsbqkbsr/p1p1p1pp/B4Q2/8/2P1PP2/P1p3K1/P6P/RSB3SR

> 32 single moves      C+

>

> Solution

> 1.Pe2-e4   Pf7-f5   2.Bf1-a6   Pf5-f4   3.Pc2-c4   Pf4-f3

> 4.Sb1-c3   Pf3xg2   5.Qd1-f3   Pb7-b5   6.Qf3-f6   Pb5-b4

> 7.Pf2-f4   Pb4-b3   8.Sg1-f3   Pg2-g1=B 9.Sc3-e2   Bg1-c5

> 10.Se2-g1   Bc5-a3   11.Pb2xa3   Pb3-b2   12.Ke1-f2   Pb2-b1=S

> 13.Kf2-g3   Sb1-c3   14.Pd2xc3   Pd7-d5   15.Sf3-d2   Pd5-d4

> 16.Sd2-b1   Pd4xc3

>

> Mutual NN sibling (6 moves) motivated by double Ceriani-Frolkin with

> promotions on

> the knights' home squares. Black side finished officer homebase.

>

> ------------------------------------------------------------------------------------------------

> Jorge Lois & Roberto Osorio

> Argentina

> 1s1qb1sr/p1p2p1p/p2k1p1p/3p3r/8/2P5/PP2PP1P/RSBQKB1R

> 39 single moves. 13 + 15       C+

>

> Solution

> 1.Pd2-d4   Sb8-c6   2.Qd1-d3   Ra8-b8   3.Qd3-a6   Pb7xa6

> 4.Sg1-f3   Rb8-b5   5.Sf3-h4   Rb5-h5   6.Sh4-f5   Pd7-d5

> 7.Sf5-h6   Pg7xh6   8.Pg2-g4   Bf8-g7   9.Pg4-g5   Bg7-e5

> 10.Pg5-g6   Sg8-f6   11.Pg6-g7   Sf6-d7   12.Pg7-g8=S Sd7-b8

> 13.Sg8-f6   Pe7xf6   14.Pd4xe5   Sc6-e7   15.Pe5-e6   Se7-g8

> 16.Pe6-e7   Ke8-d7   17.Pe7-e8=Q Kd7-d6   18.Qe8-a4   Bc8-d7

> 19.Pc2-c3   Bd7-e8   20.Qa4-d1

>

> Mutual NN sibling (6 moves) with Phenix/Ceriani-Frolkin and Pronkin.

> -----------------------------------------------------------------------------------------------


Very interesting ! Mine is unpublishable (horrible visible promoted
knight), unless if it is the shortest length record, but I doubt about
that.

1.Pd2-d3   Pc7-c5   2.Fc1-f4   Dd8-a5   3.Cb1-d2   Pb7-b6
4.Pe2-e3   Fc8-b7   5.Cg1-e2   Fb7xg2   6.Th1-g1   Fg2-h3
7.Tg1-g6   Pc5-c4   8.Tg6-f6   Pe7xf6   9.Ta1-b1   Ff8-a3
10.Pb2xa3   Pc4-c3   11.Tb1-b2   Pc3xb2   12.Ce2-c3   Pb2-b1=C
13.Cd2-f3   Cb1-d2   14.Cf3-g1   Cd2-f3   15.Re1-e2   Cf3-h4
16.Cc3-b1