What is index-1.9b?

Index-1.9B is a compact, multilingual artificial intelligence created by Bilibili. Despite its small size, it is designed to punch above its weight class, offering chat, translation, and role-playing capabilities. Think of it as a smaller, easier-to-run alternative to massive AI systems that still handles everyday conversational tasks, particularly in Chinese and other East Asian languages. The project actually includes several versions of the same underlying brain. The base model learned from a massive amount of internet text, while the chat version was trained to hold conversations and translate languages. Because it absorbed a lot of internet community content, the creators note it has a more engaging and interesting personality than typical corporate AI. There is also a role-playing version that lets you create and chat with custom characters by providing a description and a bit of dialogue history. Finally, a special long-text version can read and summarize documents of over 35,000 words in a single pass, despite being only a fraction of the size of models like GPT-4. This tool is ideal for developers or hobbyists who want to run a capable AI locally without needing expensive, high-end hardware. For example, a startup could use the chat model to power a customer service bot in Chinese, or a solo developer could experiment with the role-playing model to create interactive game characters. The long-text version is handy for anyone needing quick summaries of lengthy financial reports or research papers. The project is notably open about its training process. It even includes a "pure" version where the creators filtered out all instruction-like data from the training materials, purely to study how that affects the AI's benchmark scores. The model is fully open for academic research and supports free commercial use, making it a practical choice for building real-world applications.