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At the age of 20, Capablanca showcased his exceptional talent by triumphing in the 1909 San Sebastian Grandmasters' Tournament. This prestigious international chess event featured prominent players of the era, including Akiba Rubinstein, Siegbert Tarrasch, and Frank Marshall. Capablanca's remarkable achievement demonstrated his early dominance and marked the beginning of his rise as one of the most formidable chess players in history.