# Pairwise comparison of chess opening variations

SUMMARY: Pairwise comparisons show that there is no difference between the B70 Sicilian Defense/Dragon Variation and the B90 Sicilian Defense/Najdorf Variation in terms of the probability vector. The data are consistent with our null hypothesis that the same underlying probability vector drives game outcomes in both of these variations. The Sicilian Defense/Accelerated Dragon and Hyper Accelerated Dragon variations are found to be strategies by black that depend on white's cooperation. In both cases white is able to change the probability vector in its favor by making a move that is different from the one assumed by black. These variations are therefore not robust because in both cases black takes the risk that white will not cooperate. An interesting case is that of the two variations of the Sicilian Defense/Yugoslav Attack. They are found to be driven by different probability vectors but the difference lies in a neutral direction. The classical variation is "drawish" by comparison because it offers a higher probability of draw than the more open game initiated by the modern variation of the Yugoslav Attack.

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http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2472783

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