DeepSeek R1 is the first-generation reasoning model from DeepSeek that introduced their proprietary Chain-of-Thought (CoT) process. While significantly slower than standard models due to its intensive 'thinking' phase, it achieves state-of-the-art performance in mathematics (97.3% on MATH-500) and coding. It is designed for complex problem-solving rather than casual conversation, with a strong focus on STEM fields.