Karasu

Karasu is Lightblue's Japanese-language large language model series, released in late 2023 as one of Japan's first domestically developed open LLM efforts. The name comes from Yatagarasu, the mythical three-legged crow and god of guidance. The headline 7B model was fine-tuned for Japanese commercial use, with a 72B variant (ao-Karasu) following in March 2024.

Lightblue's team refined training data daily to squeeze strong Japanese performance out of a 7B footprint, claiming parity with larger 13B-class Japanese models of the era. The sibling Qarasu series, built on Qwen-14B, pushed further toward GPT-3.5-class Japanese MT-Bench scores. Karasu became a widely benchmarked reference point in early Japanese LLM evaluations.

The Karasu models were released for commercial use via Hugging Face and helped establish the pattern of Japanese startups fine-tuning international open bases with Japan-specific data. Weights are public, but confirm the current license on the model card before commercial deployment.