Author: Les Fernandez
Date: 17:05:07 10/17/03
Go up one level in this thread
On October 17, 2003 at 02:42:52, GuyHaworth wrote: > >I surveyed the history of the 'k-move rule' in: > >"Strategies for Constrained Optimisation", ICGA_J v23.1 pp9-20 (2000): > >Further information is welcome if there are any omissions. > > >Ruy Lopez suggested a 50-move limit in Article 17 of his Chess Code of 1561, >perhaps in the interests of his fellow coffee-house professionals who played for >wagers. The 1883 London Tournament's rules, the basis of FIDE's rules today, >were the first to state that a P-push or capture would zero the move count. > >In 1974, FIDE first enabled the 50-move rule to be varied. > >They did so, with 100-move clauses: > > - in 1978 for KNNKP > - in 1982 for KRP(a2)KbBP(a3) after the Timman-Velimirovic game > - in 1984 for KRBKR. > >John Roycroft had argued for other endgames to be given more headroom but FIDE >did not agree with his suggestions. > >By 1988, computer results were plentiful (Thompson), if not independently >2nd-sourced, and endgame-specific limits were suggested. However, FIDE adopted a >simpler stance, replacing the 100-move clauses by a 75-move clause for just six >endgames: > > - KBBKN > - KBBKQ > - KNNKP > - KNNKQ > - KQP(x7)KQ > - KRBKR > >KRPKBP with blocked Pawns ceased to be an exception at that time. > >Stiller discovered KRBKNN's maxDTC of 223 in 1991 and so, in 1992, FIDE gave up >the chase and restored the universal 50-move limit. > >KRNKNN's maxDTC = 243 was found in 1996 (and 2nd-sourced by Ken Thompson in >1999). > > >In the much more common situation with Pawns on the board, the move count can >still soar even with perfect play. KNNKP has maxDTZ = 82, a result in: > >Tamplin & H, "Chess Endgames: Data and Strategy" >ACG-10 Conference (ICGA event, Graz, Nov. 2003) Proceedings > >... and Marc Bourzutschky found, admittedly in a line minimaxing DTM(ate), a >move-count going to 165 in KRRPKQ. The actual maxDTZ of KRRPKQ is likely to be >of that order. > >The Tamplin/H paper also surveys the DTC and DTZ50 stats, and gives examples >where minimising moves to mate, conversion or P-push is exactly the wrong thing >to do to preserve a win under the 50-move rule. > > > >One could argue that chess-engine authors have every opportunity to pick up the >available EN DTM EGTs, or generate their own to DTM or another metric, and that >therefore the 50-move rule need not apply in C-C tournaments such as the >forthcoming ICGA WCCC event in Graz, Nov. 2003. > >However, if the rule is to be dispensed with, competing authors should be given >reasonable notice of this. > >I guess KNNKP and KQPKQ are the most likely to occur over the board, and of >these, KNNKP play is conspicuously the most affected by the 50-move rule. >Again, the Tamplin/H paper gives the stats. > >It is unlikely that the maxDTZ = 243 of KRNKNN will be surpassed until 7-man >EGTs are computed. Establishing maxDTZ for 6-man P-endgames is however, a >target. > 262 is the highest I know of so far!!! Les >g
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