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Subject: Crafty's "Trojan Horse" Attack Detector

Author: Ed Trice

Date: 16:04:51 05/04/04

A snippet from the Crafty evaluation routine:

/*
 ----------------------------------------------------------
|                                                          |
|   first, check for the "trojan horse" attack where the   |
|   opponent offers a piece to open the h-file with a very |
|   difficult to refute attack.                            |
|                                                          |
 ----------------------------------------------------------
*/


  if (trojan_check)
  {
    if (root_wtm && File(WhiteKingSQ) >= FILEF)
    {
      if (!(bb=tree->all_pawns&file_mask[FILEJ]).b1 && !bb.b2)
      {
        if ((BlackRooks.b1 || BlackRooks.b2) && (BlackQueens.b1 ||
BlackQueens.b2)) score-=KING_SAFETY_MATE_THREAT;
      }
    }
    if (Flip(root_wtm) && File(BlackKingSQ) >= FILEF)
    {
      if (!(bb=tree->all_pawns&file_mask[FILEJ]).b1 && !bb.b2)
      {
        if ((WhiteRooks.b1 || WhiteRooks.b2) && (WhiteQueens.b1 ||
WhiteQueens.b2)) score+=KING_SAFETY_MATE_THREAT;
      }
    }
  }


Does anyone have a concrete example of what position, or family of positions,
this code is encouraging the program to seek or avoid?

Re: Crafty's "Trojan Horse" Attack Detector Bryan Hofmann 07:48:56 05/05/04
- Re: Crafty's "Trojan Horse" Attack Detector Ed Trice 19:02:14 05/05/04
Re: Crafty's "Trojan Horse" Attack Detector Russell Reagan 18:16:08 05/04/04
- Re: Crafty's "Trojan Horse" Attack Detector Ed Trice 19:05:06 05/05/04
Re: Crafty's "Trojan Horse" Attack Detector Mike S. 17:09:01 05/04/04
- Re: Crafty's "Trojan Horse" Attack Detector Ed Trice 18:20:08 05/04/04
Re: Crafty's "Trojan Horse" Attack Detector Ed Trice 16:21:14 05/04/04

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