Yi-1.5-6B-Chat is a variant of the Yi-1.5 series, belonging to the open-source chat model. Yi-1.5 is an upgraded version of Yi, continuously pre-trained on 500B high-quality corpora and fine-tuned on over 3M diverse samples. Compared to Yi, Yi-1.5 demonstrates stronger capabilities in coding, mathematics, reasoning, and instruction following, while maintaining excellent language understanding, common sense reasoning, and reading comprehension abilities. The model is available in context length versions of 4K, 16K, and 32K, with a total pre-training volume reaching 3.6T tokens.