OpenAI's AI model, o3, emerged victorious in the Kaggle Game Arena chess tournament, held from August 5-7, 2025. The model secured a flawless 4-0 win against xAI's Grok 4 in the final match, demonstrating superior strategic capabilities. Throughout the tournament, o3 maintained a high level of performance, winning all its matches without a single loss. In the third-place playoff, Google's Gemini 2.5 Pro secured the bronze medal by defeating OpenAI's o4-mini with a score of 3.5-0.5.
The tournament, which featured general-purpose AI models rather than specialized chess engines, highlighted the rapid advancements in AI's strategic reasoning. Despite Grok 4's strong performance in earlier rounds, including a dramatic semifinal win over Gemini 2.5 Pro, it faltered in the final. Commentators like World Chess Champion Magnus Carlsen noted Grok 4's repeated blunders and a significantly lower estimated chess rating compared to o3. The event served as a benchmark for AI performance in complex, rule-based games, showcasing the ongoing competition and development in the field of artificial intelligence.