Upstage Launches Syn Pro, a Japanese-Language LLM Co-Developed With Karakuri
Upstage announced Syn Pro, a Japanese LLM co-developed with Karakuri Inc., which it says ranks top among locally trained models under 32B parameters and deploys on-premises.
Quick answer
What did Upstage announce with Syn Pro?
Upstage has released Syn Pro, a Japanese-language large language model co-developed with Karakuri Inc. Upstage says the model ranks first among locally trained Japanese LLMs under 32 billion parameters, tops the global top 20 on the Nejumi Leaderboard, and can be deployed on-premises, in private cloud, or on customer-owned GPUs.
Key takeaways
- Upstage has launched Syn Pro, a Japanese-language large language model co-developed with Karakuri Inc.
- Upstage says Syn Pro ranks first among Japanese locally trained models under 32 billion parameters and places in the global top 20 on the Nejumi Leaderboard maintained by Weights & Biases Japan.
- The company says Syn Pro can run on-premises, in a private cloud, or on a customer's own GPUs, without external API calls.
- Syn Pro joins the earlier 11-billion-parameter Syn model to form what Upstage describes as a scalable LLM family for Japan, alongside SolarBox, a joint on-premises hardware offering with HP Japan.
Upstage has released Syn Pro, a Japanese-language large language model the company co-developed with Karakuri Inc., a Japanese AI developer. The model is part of Upstage's Solar product line and was announced in a blog post published October 23, 2025.
Performance claims
Upstage says Syn Pro is Japan's top-performing locally trained LLM, ranking first among models under 32 billion parameters and placing in the global top 20 on the Nejumi Leaderboard, a benchmark maintained by Weights & Biases Japan. The company also says Syn Pro outperforms larger models, including GPT OSS-120B, on Japanese-language tasks, citing what it describes as greater precision and cultural nuance.
Deployment and data handling
According to Upstage, Syn Pro can be deployed on-premises, in a private cloud, or on a customer's own GPUs, without external API calls. Upstage says the model is used in what it calls Japan's most regulated sectors, including finance, healthcare, and government. Syn Pro also includes what Upstage calls a 'reasoning budget' feature, which the company says automatically balances speed and computational complexity.
Product family
Syn Pro joins an earlier model, Syn, which has 11 billion parameters and which Upstage says is already used in what it describes as mission-critical deployments across industries. The company describes the two models together as a scalable LLM family built for the Japanese market. Upstage also pointed to SolarBox, a joint offering with HP Japan that the company says brings its AI models into secure, on-premises hardware environments.
Who Upstage says it's for
Upstage says Syn Pro is intended for chief information officers and IT leaders bringing generative AI in-house, for legal, compliance, and risk teams, for enterprises that require on-premises or private-cloud control, for public institutions that need high accuracy in Japanese, and for developers building domain-specific applications.
Availability
Upstage says Syn Pro is available now, with access offered through the company's online console or by contacting its solutions team.
Source: Upstage, "Introducing Syn Pro," published October 23, 2025.
Frequently asked questions
- What is Syn Pro?
- Syn Pro is a Japanese-language large language model that Upstage co-developed with Karakuri Inc., released as part of Upstage's Solar product line.
- How does Upstage say Syn Pro performs against other models?
- Upstage says Syn Pro ranks first among locally trained Japanese models under 32 billion parameters, places in the global top 20 on the Nejumi Leaderboard, and outperforms larger models such as GPT OSS-120B on Japanese-language tasks.
- Where can Syn Pro be deployed?
- According to Upstage, Syn Pro can run on-premises, in a private cloud, or on a customer's own GPUs, without sending data through external API calls.
- Is Syn Pro available now?
- Upstage says Syn Pro is available now, accessible through its online console or by contacting the company's solutions team.
Sources
- Introducing Syn Pro — Upstage