3-5-man chess: Maximals and mzugs

This article reports the combined results of several initiatives in creating and surveying complete suites of endgame tables (EGTs) to the Depth to Mate (DTM) and Depth to Conversion (DTC) metrics. Data on percentage results, maximals and mutual zugzwangs, mzugs, has been filed and made available on the web, as have the DTM EGTs.

Chess endgame news

The Endgame Tables Online initiative and p2p community have made available all published Nalimov DTM EGTs. It now looks forward to the 16 unpublished EGTs computed by August 9th and presumed to be still in existence, particularly as Marc Bourzutschky’s FEG results independently confirm all Nalimov’s published 3-3p DTM EGT statistics including those for KPPKPP.

Chess endgame news

A report of the new Bourzutschky/Konoval chess endgame depth record of DTC = 330 moves, and of the progress of the Kryukov peer-group to disseminate Nalimov's DTM EGTs. The question of data integrity and assurance is raised.

Chess endgame news

News that Bourzutschky confirms there is no sub-7-man pawnless zugzwang, and that Bourzutschky and Konoval are generating DTC EGTs with a new program. News also of Kristensen's work on EGTs using OBDDs, Ordered Binary Decision Diagrams.

Chess endgame update

This is a review of progress in the Chess Endgame field. It includes news of the promulgation of Endgame Tables, their use, non-use and potential runtime creation. It includes news of data-mining achievements related to 7-man chess and to the field of Chess Studies. It includes news of an algorithm to create Endgame Tables for variants of the normal game of chess.

3-5-Man chess data

This reports the work of Karrer and Wirth in identifying percentage results and, respectively, the Depth to Mate (DTM) and Depth to Conversion (DTC) data in all 2-5-man chess endgames.

3-5-man mutual zugzwangs in chess

This note reports the work of Wirth and Karrer in twin-sourcing all mutual zugzwang positions, mzugs, in 2-5-man endgames. This paper tabulates the mzug statistical data, gives examples of maximal mzugs and refers to a chess endgame website where further data is to be found.

How soccer players head the ball: a test of optic acceleration cancellation theory with virtual reality

We measured the movements of soccer players heading a football in a fully immersive virtual reality environment. In mid-flight the ball’s trajectory was altered from its normal quasi-parabolic path to a linear one, producing a jump in the rate of change of the angle of elevation of gaze (α) from player to ball. One reaction time later the players adjusted their speed so that the rate of change of α increased when it had been reduced and reduced it when it had been increased. Since the result of the player’s movement was to regain a value of the rate of change close to that before the disturbance, the data suggest that the players have an expectation of, and memory for, the pattern that the rate of change of α will follow during the flight. The results support the general claim that players intercepting balls use servo control strategies and are consistent with the particular claim of Optic Acceleration Cancellation theory that the servo strategy is to allow α to increase at a steadily decreasing rate.

Test performance indicators from a single soccer specific fitness test differentiate between highly trained and recreationally active soccer players

Aim. The aim of this study was to investigate whether a single soccer specific fitness test (SSFT) could differentiate between highly trained and recreationally active soccer players in selected test performance indicators. Methods. Subjects: 13 Academy Scholars (AS) from a professional soccer club and 10 Recreational Players (RP) agreed to participate in this study. Test 1-(V)over dotO(2) max was estimated from a progressive shuttle run test to exhaustion. Test 2-The SSFT was controlled by an automated procedure and alternated between walking, sprinting, jogging and cruise running speeds. Three activity blocks (1A, 2A and 3A) were separated by 3 min rest periods in which blood lactate samples were drawn. The 3 blocks of activity (Part A) were followed by 10 min of exercise at speeds alternating between jogging and cruise running (Part B). Results. Estimated (V)over dotO(2) max did not significantly differ between groups, although a trend for a higher aerobic capacity was evident in AS (p<0.09). Exercising heart rates did not differ between AS and RP, however, recovery heart rates taken from the 3 min rest periods were significantly lower in AS compared with RP following blocks 1A (124.65 b(.)min(-1) +/-7.73 and 133.98 b(.)min(-1) +/-6.63), (p<0.05) and 3A (129.91 b.min(-1) +/-10.21 and 138.85 b.min(-1) +/-8.70), (p<0.01). Blood lactate concentrations were significantly elevated in AS in comparison to RP following blocks 2A (6.91 mmol(.)l(-1) +/-2.67 and 4.74 mmol(.)l(-1) +/-1.28) and 3A (7.18 mmol(.)l(-1) +/-2.97 and 4.88 mmol(.)l(-1) +/-1.50), (p<0.05). AS sustained significantly faster average sprint times in block 3A compared with RP (3.18 sec +/-0.12 and 3.31 sec +/-0.12), (p<0.05). Conclusion. The results of this study show that highly trained soccer players are able to sustain, and more quickly recover from, high intensity intermittent exercise.

Chess endgame knowledge advances

This review of recent developments starts with the publication of Harold van der Heijden's Study Database Edition IV, John Nunn's second trilogy on the endgame, and a range of endgame tables (EGTs) to the DTC, DTZ and DTZ50 metrics. It then summarises data-mining work by Eiko Bleicher and Guy Haworth in 2010. This used CQL and pgn2fen to find some 3,000 EGT-faulted studies in the database above, and the Type A (value-critical) and Type B-DTM (DTM-depth-critical) zugzwangs in the mainlines of those studies. The same technique was used to mine Chessbase's BIG DATABASE 2010 to identify Type A/B zugzwangs, and to identify the pattern of value-concession and DTM-depth concession in sub-7-man play.

Data-mining chess databases

This is a report on the data-mining of two chess databases, the objective being to compare their sub-7-man content with perfect play as documented in Nalimov endgame tables. Van der Heijden’s ENDGAME STUDY DATABASE IV is a definitive collection of 76,132 studies in which White should have an essentially unique route to the stipulated goal. Chessbase’s BIG DATABASE 2010 holds some 4.5 million games. Insight gained into both database content and data-mining has led to some delightful surprises and created a further agenda.

Uniqueness in chess studies

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.

Zugzwangs in chess studies

Van der Heijden’s ENDGAME STUDY DATABASE IV, HHDBIV, is the definitive collection of 76,132 chess studies. The zugzwang position or zug, one in which the side to move would prefer not to, is a frequent theme in the literature of chess studies. In this third data-mining of HHDBIV, we report on the occurrence of sub-7-man zugs there as discovered by the use of CQL and Nalimov endgame tables (EGTs). We also mine those Zugzwang Studies in which a zug more significantly appears in both its White-to-move (wtm) and Black-to-move (btm) forms. We provide some illustrative and extreme examples of zugzwangs in studies.

Chess endgame news

Reports the availability on the web of the entire run of Beasley's 'British Endgame Study News', and reviews a recent report by Bourzutschky and Konoval on their discoveries with 7-man endgame tables.