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Uniqueness in chess studies

By Guy McC. Haworth, Eiko Bleicher and H. M. J. F. van der Heijden


Van der Heijden’s ENDGAME STUDY DATABASE IV, HhdbIV, is the definitive collection of 76,132 chess studies. In each one, White is to achieve the stipulated goal, win or draw: study solutions should be essentially unique with minor alternatives at most. In this second note on the mining of the database, we use the definitive Nalimov endgame tables to benchmark White’s moves in sub-7-man chess against this standard of uniqueness. Amongst goal-compatible mainline positions and goal-achieving moves, we identify the occurrence of absolutely unique moves and analyse the frequency and lengths of absolutely-unique-move sequences, AUMSs. We identify the occurrence of equi-optimal moves and suboptimal moves and refer to a defined method for classifying their significance

Publisher: The International Computer Games Association
Year: 2011
OAI identifier:

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  1. (2003). Depth and Beauty: The chess endgame studies of
  2. For example, a class of moves quickly seen as TWMs include many where White safely reverses its previous move.
  3. is not the only metric, there will be positions where DTM-suboptimal but DTx-optimal moves are best.
  4. Q7/8/8/7K/7p/8/7p/6k1 w, position 7w in Aloni Study HHdbIV31073: White and Black are in effect minimaxing moves to KQK rather than to mate or conversion of force. Thus, White plays 7.Qa1+ rather than 7.Qg8+.
  5. With format (HHdbIV study index, AUMS length and start of AUMS), they are:

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