Automatic Detection of Metaphorical Expressions in Classical Japanese Using WLSP-Enhanced BERT

Hang Zhu, Mitoki Ohara, Rei Kikuchi, Kanako Komiya, Masayuki Asahara, Sachi Kato


Abstract
Metaphor detection is a fundamental task in natural language processing, yet research on historical languages remains limited. While progress has been made in modern Japanese metaphor detection, classical Japanese texts present unique challenges due to their distinct vocabulary, grammar, and metaphorical patterns. This paper addresses this gap by applying a BERT-based metaphor detection method enhanced with semantic classification information from the Word List by Semantic Principles (WLSP) to classical Japanese texts. We evaluate our approach on CHJ-Metaphor, a newly available corpus featuring metaphor annotations for three medieval Japanese works from the Corpus of Historical Japanese (CHJ). Our method achieves an F1-score of 82.18 through 5-fold cross-validation. Notably, qualitative analysis by domain experts reveals that our model successfully identifies genuine metaphors overlooked during manual annotation, demonstrating its potential as a tool for improving annotation quality in large-scale corpus construction. These results confirm the effectiveness of WLSP-enhanced approaches for metaphor detection in classical Japanese and suggest promising directions for applying similar techniques to other historical languages.
Anthology ID:
2026.lt4hala-1.8
Volume:
Proceedings of the Fourth Workshop on Language Technologies for Historical and Ancient Languages (LT4HALA 2026) @ LREC 2026
Month:
May
Year:
2026
Address:
Palma, Mallorca (Spain)
Editors:
Rachele Sprugnoli, Marco Passarotti
Venues:
LT4HALA | WS
SIG:
Publisher:
ELRA Language Resources Association (ELRA)
Note:
Pages:
89–95
Language:
External URL:
https://lrec.elra.info/lrec2026-ws-lt4hala-08
DOI:
10.63317/2ptf9cfgpkgz
Bibkey:
Cite (ACL):
Hang Zhu, Mitoki Ohara, Rei Kikuchi, Kanako Komiya, Masayuki Asahara, and Sachi Kato. 2026. Automatic Detection of Metaphorical Expressions in Classical Japanese Using WLSP-Enhanced BERT. In Proceedings of the Fourth Workshop on Language Technologies for Historical and Ancient Languages (LT4HALA 2026) @ LREC 2026, pages 89–95, Palma, Mallorca (Spain). ELRA Language Resources Association (ELRA).
Cite (Informal):
Automatic Detection of Metaphorical Expressions in Classical Japanese Using WLSP-Enhanced BERT (Zhu et al., LT4HALA 2026)
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