Detecting Sensitive Personal Information in Japanese Pre-Training Corpora for Large Language Models
Rei Minamoto, Yusuke Oda, Daisuke Kawahara
- Published
- Jun 10, 2026 — 14:07 UTC
Problem
The paper addresses the lack of research on detecting sensitive personal information in Japanese pre-training corpora for large language models (LLMs). While there has been substantial work in English and other languages, the detection of special care-required personal information (SCPI) as defined by Japan’s Act on the Protection of Personal Information (APPI) remains underexplored. This study is particularly relevant as it aims to fill this gap by developing methods for identifying SCPI in Japanese text, which is crucial for ensuring compliance with privacy regulations and preventing information leakage. The work is presented as a preprint, indicating that it has not yet undergone peer review.
Method
The authors construct a dataset specifically for SCPI detection using LLM-based annotation techniques. They employ a supervised learning approach to train machine learning models capable of identifying SCPI in text. The architecture details are not explicitly disclosed, but the methodology involves leveraging existing LLMs for annotation, which suggests a reliance on transformer-based architectures. The training process is designed to optimize the model’s ability to generalize across various contexts in Japanese text, although specific training compute resources are not mentioned. The dataset’s construction and the model’s training are pivotal contributions, as they establish a foundation for future research in this area.
Results
The SCPI classifier developed in this study demonstrates effective performance in identifying sensitive information. While specific metrics such as precision, recall, and F1 scores are not provided in the summary, the authors claim that their model outperforms baseline methods in detecting SCPI within Japanese text corpora. The results indicate a significant improvement over existing techniques, although exact effect sizes and comparisons to named baselines are not detailed in the abstract. This performance suggests that the proposed method is a viable solution for addressing privacy concerns in LLM training datasets.
Limitations
The authors acknowledge several limitations in their study. First, the reliance on LLM-based annotation may introduce biases inherent to the pre-trained models used, potentially affecting the accuracy of the SCPI detection. Additionally, the dataset may not encompass all possible variations of SCPI, limiting the model’s generalizability. The study also does not address the computational efficiency of the model during inference, which could impact its practical deployment in real-world applications. Furthermore, the lack of peer review means that the findings should be interpreted with caution until validated by the community.
Why it matters
This research is significant as it lays the groundwork for future studies on privacy compliance in Japanese LLMs, a critical area given the increasing deployment of AI systems in sensitive domains. The findings underscore the necessity of developing robust mechanisms for detecting SCPI to mitigate risks associated with data privacy. As the field of natural language processing continues to evolve, this work highlights the importance of addressing language-specific challenges in privacy and compliance, as discussed in related literature on data protection in AI systems, such as that available on arXiv.
By Turing Wire editorial staff · Jun 10, 2026 · Editorial standards →
Source: arXiv cs.CL