Fast Algorithm for Calculating Probability of Chess Winning Streaks
Guoqing Diao
TL;DR
The paper addresses exact probability calculations for streaks in sequences of $n$ games given per-game outcomes, deriving recurrence-based procedures for three streak types. It develops a recurrence framework for the pure streak via $p_{m,k}$, extends to non-losing streaks by aggregating outcomes, and handles the in-between streak with a three-outcome model using $D_{m,k+1/2}$ and $g_{m,k+1/2}$ alongside a tractable approximation for $h_{a,b,k}$. The contributions include closed-form-like recurrences for exact at-least-one-streak probabilities, a fast C implementation, and numerical studies validating accuracy and scalability to large $n$ and $k$. The approach provides conservative bounds under independence and broad applicability to other domains with known per-game probabilities, such as online gaming or sports analytics.
Abstract
Motivated by the controversy in the chess community, where Hikaru Nakamura, a renowned grandmaster, has posted multiple impressive winning streaks over the years on the online platform chess.com, we derive the probabilities of various types of streaks in online chess and/or other sports. Specifically, given the winning/drawing/losing probabilities of individual games, we derive the probabilities of "pure" winning streaks, non-losing streaks, and "in-between" streaks involving at most one draw over the course of games played in a period. The performance of the developed algorithms is examined through numerical studies.
