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- - By Quibbly34 (*) Date 2008-08-12 12:15
J.Barbier/F.Saavedra
Glasgow Weekly Citizen, 1895

1.c7 Rd6+ 2.Kb5 Rd5+ 3.Kb4 Rd4+ 4.Kc3 Rd1 5.Kc2 Rd4!? [5...Rf1 6.c8Q Rf2+ 7.Kd1 Rf1+ 8.Ke2 Rb1 and White has to win with queen against rook.] 6.c8R!! [6.c8Q? Rc4+!! 7.Qxc4 stalemate.] 6...Ra4 7.Kb3 Rh4 8.Rc1# +-

New game - Fritz 11
8/8/1KP5/3r4/8/8/8/k7 w - - 0 1


In this famous study Rybka 3 after a few seconds incorrectly evaluates the position as a draw failing to see the crucial underpromotion to a rook on move six - Rybka 2.3.2a has no problem

Analysis by Rybka 3 32-bit :

1.c7
  +-  (4.02)   Depth: 2   00:00:00
1.c7
  +-  (4.02)   Depth: 3   00:00:00
1.c7
  +/=  (0.68)   Depth: 4   00:00:00
1.c7
  +-  (3.58)   Depth: 6   00:00:00
1.c7
  +-  (3.58)   Depth: 6   00:00:00  0kN
1.c7
  +-  (3.58)   Depth: 6   00:00:00  0kN
1.c7
  +-  (3.58)   Depth: 6   00:00:00  0kN
1.c7
  +-  (3.58)   Depth: 6   00:00:00  0kN
1.c7
  +-  (3.58)   Depth: 6   00:00:00  0kN
1.c7 Rd6+ 2.Kb5 Rd5+
  +-  (4.16)   Depth: 6   00:00:00  1kN
1.c7 Rd6+ 2.Kb5 Rd2 3.c8Q
  +-  (4.26)   Depth: 7   00:00:00  5kN
1.c7 Rd3 2.c8Q Kb2
  +-  (4.09)   Depth: 8   00:00:00  12kN
1.c7 Rd3 2.c8Q Rb3+ 3.Ka5 Kb2 4.Qe6
  +-  (4.16)   Depth: 9   00:00:00  15kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.18)   Depth: 10   00:00:00  18kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 13   00:00:00  19kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 13   00:00:00  19kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 13   00:00:00  19kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 14   00:00:00  19kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 15   00:00:00  20kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 16   00:00:00  22kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 17   00:00:00  25kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 18   00:00:00  29kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 19   00:00:00  37kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 20   00:00:00  45kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 21   00:00:01  60kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 22   00:00:01  79kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 23   00:00:02  111kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 24   00:00:02  164kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 25   00:00:03  208kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 26   00:00:06  365kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 27   00:00:06  367kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 28   00:00:25  1550kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 29   00:00:25  1550kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 30   00:00:25  1550kN
1.c7 Rd6+ 2.Kb7 Rd7 3.Kb8 Rxc7 4.Kxc7 Kb2 5.Kc6 Kc3 6.Kc5 Kd3 7.Kd5 Kc3 8.Kc5 Kd3 9.Kd5 Kc3 10.Kc5 Kd3 11.Kd5 Kc3 12.Kc5 Kd3 13.Kd5 Kc3 14.Kc5 Kd3 15.Kd5 Kc3 16.Kc5
  =  (0.00)   Depth: 31   00:00:25  1550kN
Parent - - By Arkansaw (***) Date 2008-08-12 12:45
tablebase = yes?
Parent - - By Quibbly34 (*) Date 2008-08-12 14:08
You are right, just thought it was interesting that Rybka 2.3.2a could find the solution without tablebases. Wonder if its a problem regarding underpromotions could show itself in situations with more than >7 pieces where tablebases are unavailable.

I guess I'm being a little picky - Rybka 3 is a amazing chess program!!
Parent - - By Quibbly34 (*) Date 2008-08-12 15:04
Just installed Rybka 3 sp onto my Fritz 11 interface & the problem disappeared.

Seems to be a problem with the MP version!!

Nil Desperandum
Parent - By nine castles (**) Date 2008-08-12 16:14
If true that would be very interesting and I would like the devs to take a look at this.

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