ByteDance is training an AI model that could approach the size of Anthropic’s most cutting-edge Mythos system, as Chinese companies continue to narrow the gap with the top US labs. The ByteDance model is being pre-trained—a stage that typically takes three to six months—before it is fine-tuned and released if all goes well, one of the people said. The exact model size would only be determined at a later stage. In the past weeks alone, Chinese models from Moonshot and Alibaba show strong performance on benchmarks, lagging behind only Anthropic’s Fable 5 in certain areas. Mythos 5, Anthropic’s most advanced model, is only available to approved organizations after a temporary ban in June due to security concerns.