Computer Chess Club Archives

Search

Messages

Subject: Re: Help with strange tablebase output - Crafty-18.6 & Fritz6

Author: jonas cohonas

Date: 13:53:06 03/16/01

Go up one level in this thread

On March 16, 2001 at 16:02:20, John Hatcher wrote:

>Here is a position arising from Rueben Fine's "Basic Chess Endings", No. 309b -
>
>[D]r7/4P1k1/3K4/8/8/8/8/5R2 w
>
>White wins after 1. Ra1.  This solution was found instantly (of course) by both
>Wcrafty-18.6 (using Winboard) and Fritz6, both using the same 5-piece Nalimov
>tablebases.
>
>But now it gets strange.  What if White temporizes first with 1. Rg1+  Kf7,
>arising at this position:
>
>[D]r7/4Pk2/3K4/8/8/8/8/6R1 w
>
>Wcrafty-18.6 instantly finds the win after 2. Rf1+  Kg7 (not 2. ...Ke8? 3. Rf8#)
>3. Ra1, transposing into the first position.  However, Fritz6 doesn't see the
>win!?  It's engine output reads:
>
>Analysis by Fritz 6:
>
>1. = (0.03): 10.e8R Rxe8 11.Rf1+ Kg6 12.Kd5 Kg5 13.Rf7 Rd8+ 14.Ke5 Re8+
>2. = (0.00): 10.Re1
>3. = (0.00): 10.Rh1
>4. = (0.00): 10.Rd1
>5. = (0.00): 10.Ke5
>6. = (0.00): 10.Kd5
>
>How can Fritz6 see the win in the first position and not see it in the second?
>The most obvious move, 2. Rf1+, isn't even listed in the engine output!?
>
>What's going on here?  Can anyone duplicate this strange output?
>
>JOHN

Deep Fritz finds it intantly
New position
r7/4Pk2/3K4/8/8/8/8/6R1 w - -
Analysis by Deep Fritz:

2.e8Q+--
  ±  (0.75)   Depth: 1/3   00:00:00
2.e8Q+-- Rxe8
  =  (0.13)   Depth: 1/3   00:00:00
2.Re1!
  +-  (1.63)   Depth: 1/4   00:00:00
2.Re1!
  +-  (2.53)   Depth: 1/4   00:00:00
2.Rf1+!
  +-  (2.78)   Depth: 1/4   00:00:00
2.Rf1+--
  =  (0.00)   Depth: 2/3   00:00:00
2.Rf1+--
  =  (0.00)   Depth: 2/7   00:00:00
2.Rc1!
  =  (0.00)   Depth: 2/7   00:00:00
2.Rc1! Ra6+ 3.Kd5 Kxe7
  =  (0.16)   Depth: 2/8   00:00:00
2.Re1!
  +-  (1.44)   Depth: 2/8   00:00:00
2.Re1! Ke8
  +-  (1.91)   Depth: 2/8   00:00:00
2.Re1 Ke8 3.Ke6 Ra6+ 4.Kd5
  +-  (1.75)   Depth: 3/8   00:00:00
2.Re1 Ke8 3.Ke6 Ra6+ 4.Kd5
  +-  (1.75)   Depth: 4/10   00:00:00  1kN
2.Rf1+! Kg7
  +-  (#31)   Depth: 4/10   00:00:00  2kN, tb=2
2.Rf1+ Kg7
  +-  (#31)   Depth: 5/5   00:00:00  2kN, tb=4

(, MyTown 17.03.2001)

• Re: Help with strange tablebase output - Crafty-18.6 & Fritz6 John Hatcher 14:08:21 03/16/01
  • Re: Help with strange tablebase output - Crafty-18.6 & Fritz6 James T. Walker 17:22:59 03/16/01
    • Re: Help with strange tablebase output - Crafty-18.6 & Fritz6 Chessfun 15:46:50 03/17/01
    • Re: Help with strange tablebase output - Crafty-18.6 & Fritz6 Uri Blass 00:11:30 03/17/01
• Goliath light does not see it at 2500 kN/s jonas cohonas 13:57:30 03/16/01
  • Re: Goliath light does not see it at 2500 kN/s John Hatcher 14:16:29 03/16/01

This page took 0 seconds to execute

Last modified: Thu, 15 Apr 21 08:11:13 -0700

Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.