Shisa V2 405B

Shisa V2 405B is the flagship of Shisa.AI's bilingual Japanese-English model family, released June 3, 2025. Built on Llama 3.1 405B Instruct with a synthetic JA/EN post-training recipe plus Korean and Traditional Chinese data, it surpassed GPT-4 and GPT-4 Turbo on the team's JA/EN eval suites and rivals GPT-4o and DeepSeek-V3 on Japanese MT-Bench.

It is available on Hugging Face under the Llama 3.1 Community License, with the open-sourced Shisa V2 JA/EN synthetic dataset alongside it. Training the full 405B fine-tune required DeepSpeed ZeRO-3 offloading, gradient accumulation, and sequence parallelism to fit in H100 memory.