Changes

=Metrics=

'''Depth to Mate'''

'Mate' is the ultimate goal and ends the game. For each position that is represented, 'DTM' indicates the theoretical value, and the number of winner's moves to 'Mate' if won/lost - assuming that the winner is minimizing and the loser is maximizing DTM.

'''Depth to Conversion'''

'Conversion' is the changing of the force on the board, by capture and/or Pawn-conversion. For each position that is represented, 'DTC' indicates the theoretical value, and the number of winner's moves to the goal of 'Won Conversion' if won/lost - assuming that the winner is minimizing and the loser is maximizing DTC. DTC <span style="font-family: Symbol;">£ </span>DTM.

'''Depth to Zeroing (of the ply count)'''

The ply-count is zeroed if and only if a Pawn is pushed or a capture is made. For each position that is represented, 'DTZ' indicates the theoretical value, and the number of winner's moves to the goal of 'Win and ply-count zeroed' if won/lost - assuming that the winner is minimizing and the loser is maximizing DTZ. DTZ <span style="font-family: Symbol;">£ </span>DTC <span style="font-family: Symbol;">£ </span>DTM.

'''Depth to Zeroing (of the ply count) in the context of the ''50-Move'' ''Rule'''''

The DTC, DTM and DTZ metrics do not consider the current FIDE [[Fifty-move Rule|50-move rule]] whereby a game in which no [[Irreversible Moves|irreversible moves]] have been played for 100 plies can be claimed as a draw by the player 'on move'. In this metric, in addition to the DTC/DTM/DTZ ''draws'', positions requiring more than 50 winner's moves to zero the ply-count are defined as ''draws''. DTZ <span style="font-family: Symbol;">£ </span>DTZ50 if DTZ50 <span style="font-family: Symbol; font-size: 14.66px;">¹ </span>''draw.'' 'DTZ50' is one of a set of 'DTZk' rules: a ''k''-''move rule'' effectively applies if there are only ''k'' moves left before a draw-claim might be made. ''k1'' <span style="font-family: Symbol;">£ </span>''k2'' implies ''DTZk2'' <span style="font-family: Symbol;">£ </span>''DTZk1 if DTZk1'' <span style="font-family: Symbol; font-size: 14.66px;">¹ </span>draw.

Note that, because depth is measured in winner's moves rather than plies, this metric does '''not''' define as ''draw'' a position in which 50 winner's moves and 51 loser's moves are required to zero the ply-count, despite the fact that the loser would claim a draw after 100 plies had been played in that endgame.

'''Depth by the (''k''-move) Rule'''

'The Rule' referred to here is a notional set of ''k''-move rules. For each position that is represented, 'DTR' indicates the theoretical value and, for won/lost positions'','' the least ''k'' for which DTZ''k'' is not ''draw'' - assuming that the winner is minimising and the loser is maximising DTR. DTZ <span style="font-family: Symbol;">£ </span>DTR. No DTR EGTs have been created to date <ref>[http://kirill-kryukov.com/chess/discussion-board/viewtopic.php?f=6&t=3934 DTR is no good!] by [[Harm Geert Muller]], [[Computer Chess Forums|CCRL Forum]], September 24, 2008</ref> .

'''Depth to Zeroing move, give that DTR is being minimaxed'''

If DTR = ''draw'', then DTZR = ''draw''. Otherwise, Otherwise DTRZR indicates the theoretical value, and the number of winner's moves to the zeroing of the ply count, given that the two sides are minimaxing first DTR and then DTZR. DTZR would be used in conjunction with DTR to progress a deep win in the context of a ''k''-move rule because DTR can remain unchanged over a sequence of moves. DTZR <span style="font-family: Symbol;">£ </span>DTR but it is not always the case that DTZ <span style="font-family: Symbol;">£ </span>DTZR as may seem intuitively obvious: the loser may zero the move-count to maximise DTR.