[Retros] shortest proofgames of castling switchback

[Mario Richter]

"Noam Elkies" <elkies at math.harvard.edu> writes:


> in 20.5 (switchback is completed after 19.5):

>   1 g3 a5  2 Bg2 Ra6  3 Be4 Rf6  4 Nf3 d6  5 0-0 Qd7  6 Kh1 Qh3

>   7 Rg1 Qf1  8 b3 Bh3  9 Ba3 Rf5  10 Qc1 f6  11 Qb2 Kf7  12 Qd4 Kg6

>   13 Nc3 Qb1  14 Bc1 Kh5  15 Rg2 g6  16 Kg1 Bh6  17 Kf1 Bg5  18 Ke1 Nh6

>   19 Rg1 Rf8  20 Rh1 Ng8  21 Ng1

> 

>   . n . . . r n .  hg-20.5

>   . p p . p . . p

>   . . . p . p p .

>   p . . . . r b k

>   . . . Q B . . .

>   . P N . . . P b

>   P . P P P P . P

>   R q B . K . N R  16+16

> 

>   NDE 17.vii.2007

> 

> ... Does this work?


Maybe you should put the black rook Rf8 on e8 instead,
otherwise the following cook is possible:

1.g2-g3 a7-a5 2.Bf1-g2 g7-g6 3.Bg2-e4 Bf8-h6 4.Ng1-f3 Ra8-a6 
5.O-O Ra6-f6 6.Kg1-h1 d7-d6 7.Rf1-g1 Qd8-d7 8.b2-b3 Qd7-h3 
9.Bc1-a3 Qh3-f1 10.Qd1-c1 Bc8-h3 11.Qc1-b2 Rf6-f5 
12.Qb2-d4 f7-f6 13.Nb1-c3 Qf1-b1 14.Ba3-c1 Bh6-g5 
15.Rg1-g2 Ng8-h6 16.Kh1-g1 O-O 17.Kg1-f1 Kg8-g7
18.Kf1-e1 Nh6-g8 19.Rg2-g1 Kg7-h6 20.Rg1-h1 Kh6-h5 21.Nf3-g1 

Best,

  mario