Tokyo, October 29, 2025 –AI inside Inc., a provider of an AI platform, announces that it has released a major update to its in-house developed large language model (LLM), upgrading “PolySphere-3” to “PolySphere-4.”

With this update, the model has evolved into a more versatile, general-purpose LLM, enabling a broader range of applications from business operations to system development. 
 

“PolySphere-3” has specialized in Japanese document processing, achieving highly accurate recognition performance and operational stability suitable for business use through verification with real-world data. Building on these strengths, “PolySphere-4” further enhances more general-purpose capabilities. 
 

1. Average OCR accuracy of 99.6% for non-standard documents*1

For a wide variety of documents, including non-standard forms and handwritten materials, PolySphere-4 achieved an average OCR accuracy of 99.6%, surpassing the 95.1% average accuracy of “PolySphere-3.”

*1 Related press release: AI inside Implements In-House Developed LLM “PolySphere-4” in “DX Suite,” Achieving 99.6% OCR Accuracy  
 

2. Enables RAG through enhanced information recognition and structuring 

By strengthening information recognition and structuring, PolySphere-4 supports a wide range of intellectual processing tasks, including generation, summarization, classification, and extraction. It enables RAG (retrieval-augmented generation) and data integration, seamlessly supporting processes from data digitization to utilization. 
 

3. Improves response reliability via web and internal database retrieval 

By cross-referencing web information and internal databases, the model can autonomously verify the accuracy of information. Referencing web and internal data  enhances the reliability of responses and extracted content. 
 

4. Application development through source code generation 

PolySphere-4 can generate source code from natural language, enabling the development of applications and business connectors. This streamlines system development and operational integration.

AI inside will continue to advance the performance of its LLMs and their implementation into products under its philosophy of “contributing to human evolution and well-being through AI,” promoting the social implementation of AI technologies and the creation of new value. 
 

About AI inside Inc. 

AI inside is a tech company engaged in the research, development, and social implementation of generative AI, large language models (LLMs), and autonomous AI. We have developed the Japanese-language-optimized large language model “PolySphere” and have delivered our solutions to over 3,000 organizations, including government agencies, local municipalities, and private enterprises, while continuing to advance the development and adoption of our proprietary AI infrastructure. Our flagship product, “DX Suite,” is an AI Agent designed to automate the entire workflow surrounding data entry tasks. Through these initiatives, we promote collaboration between humans and AI, realizing a “VALUE SHIFT” that transforms time saved through productivity and efficiency improvements to higher-value work.
Website: https://inside.ai/en
 

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