*Important: The transition year of the Double-Year Calendar had previously been miscalculated by one year. Please use the updated version released on or after September 16, 2025.(Note: Core arguments, such as the identification of the Five Kings of Wa and the correlation with the Wei Zhi [Records of Wei], remain unchanged.) This is the original Japanese-language version of the paper titled “Observations on the Nihon Shoki from the Perspective of the Spring-Autumn Double-Year Calendar System.” The paper introduces a novel hypothesis that the Nihon Shoki recorded reign years using a Spring-Autumn double-year calendar system until the mid-5th century, and that this misunderstanding may have led to chronological inconsistencies in modern Japanese historiography. By applying this structural reinterpretation, the paper successfully reconciles inconsistencies between the Nihon Shoki, Chinese dynastic records (including the Wei Zhi and Song Shu), and key archaeological findings such as the Inariyama Sword inscription. The present version is written in Japanese and intended for readers who wish to engage with the argument in the original language of its development. Note on Wikipedia usage.Entries in References that point to Wikipedia (or other web sources in parentheses) were consulted only for spot fact-checking of non-copyrightable facts—for example, the identity of an early proponent of the Spring–Autumn double-year system, the presence or absence of specific embassy years during the period of the Five Kings of Wa, and the measured length of the Hashihaka Kofun. No copyrightable textual expression, table structures, or images from Wikipedia were reproduced or adapted. All analyses and chronological reconstructions (including the 470 CE switch) are original and based on primary sources. Revision History ・Three updates in September 2025 (15, 16, 26) ・August 2025 **“Please refer to the end of the text for the change log.While none of the revisions affect the overall argument, some corrections—including those beyond numerical details—should be noted.”** Author's Note:This paper is licensed under CC BY-NC-SA 4.0. (Uses outside the following conditions—such as for commercial purposes or without the ShareAlike provision—require prior permission.) ・Attribution (BY): The author's name must be credited.・NonCommercial (NC): Free for non-commercial use, including summaries and translations. Commercial use requires prior permission.・ShareAlike (SA): Any derivative works (including summaries, adaptations, etc.) must be released under the same license (CC BY-NC-SA 4.0). This interpretive model is proposed independently in this paper and does not follow existing academic chronologies.It presents an original chronological interpretation based on the use of a biennial calendar prior to A.D. 469 and a reinterpretation of imperial reign years as indicators of longevity. Contact:For inquiries regarding this work (including permissions for commercial use), please visit the following website:https://tsurezureblog.sakuraweb.com/contact E-mail :h.shiina.contact@gmail.com