Upstage Unveils Syn Pro: A State-of-the-Art Japanese Language Model

On October 23, 2025, in Tokyo, Upstage AI Corporation announced the launch of its next-generation large language model (LLM), Syn Pro. Developed domestically in collaboration with Karakuri, a leading Japanese AI company, Syn Pro is set to redefine the future of AI in Japan. Notably, it has already garnered global recognition, ranking first in Japanese language performance among models with under 32 billion parameters, according to the Nejumi Leaderboard4 curated by Weights & Biases Japan. This remarkable model surpasses larger models, such as GPT OSS-120B, in accuracy and cultural context comprehension, effectively addressing the high standards of Japanese industries.

Syn Pro is specifically designed for Japanese enterprises and public institutions, ensuring deep alignment with language, regulations, and cultural aspects. Moreover, it offers the flexibility to be fully deployed in on-premises, private cloud, or dedicated hardware environments, making it suitable for a variety of applications.

Hiroyuki Matsushita, CEO of Upstage Japan, stated: "Syn Pro is not just a high-performance language model; it's a reliable LLM developed for Japanese companies. Our aim is to empower Japanese business users to achieve effective outcomes safely. In fields such as finance, healthcare, legal services, and government, merely understanding Japanese is not enough. The model must meet the highest standards for authenticity, security, and cultural context. We have designed Syn Pro in collaboration with Karakuri to ensure that users can leverage AI with complete data management and peace of mind."

Key Features of Syn Pro

1. Secure AI Implementation in Local Environments
Syn Pro allows for flexible deployment in on-premises or private cloud environments, enabling businesses to establish a secure data environment. The design minimizes the risk of external API calls or data leaks, making it ideal for industries with stringent compliance and privacy requirements.

2. Exceptional Japanese Language Accuracy and Context Understanding
Outfitted with deep optimization for nuances, culture, and business logic in Japanese, Syn Pro has already earned trust from leading companies in sectors like insurance, finance, and legal, where precision and nuance are paramount.

3. Efficient and High-Performance Architecture
With less than 32B parameters, Syn Pro delivers Japanese language performance that surpasses much larger global models. Its engineering maintains the performance of frontier models while benefiting from fine-tuning by domestic development teams, allowing for implementation in lightweight infrastructure. Additionally, the unique "Reasoning Budget" feature optimizes speed and complexity dynamically according to tasks, ensuring stable production operations.

Expanding the Syn LLM Family for the Japanese Market

As part of its expansion into the Japanese market, Syn Pro joins the ranks of the Syn (11B) model, which supports core business operations across multiple industries. The Syn series caters to diverse needs—from lightweight setups to high-end reasoning tasks—facilitating safe and reliable AI application. This vision is also showcased in the workstation-type collaborative solution "SolarBox" displayed in partnership with HP Japan, which aims to provide the secure infrastructure needed for companies and public agencies to utilize generative AI while retaining full data control.

Primary Target Audience for Syn Pro

- CIOs and IT leaders looking to deploy generative AI internally
- Legal, compliance, and risk departments seeking verifiable and secure AI
- Enterprises prioritizing data management in on-premises or private cloud settings
- Public institutions demanding high-precision Japanese processing
- Developers and builders constructing AI applications for specific domains

About Upstage

Upstage is a global AI startup offering generative AI solutions that balance safety and high performance, with backing from Amazon and AMD. The company has released a new generation of large language models specialized in Japanese, delivering reliable and precise AI tailored to the context of Japan. Leading global enterprises in sectors like insurance, legal, and healthcare utilize Upstage's technology to transform complex, unstructured documents into actionable business value.

For further inquiries, please contact:
Upstage AI Corporation
E-mail: [email protected]