The English-language sources available for this short profile are limited, leaving it heavily dependent on Richard Fuller's Shokan: Hirohito's Samurai, published in 1992. The book is considered useful, but its particular perspective and flaws constrain the account. The discussion does not specify those flaws in detail. Additional books requiring translation had been ordered to support longer studies of Japanese officers. The assessment of Oikawa remains provisional while that wider material is unavailable.
Notable Point · 12:43-13:44
Richard Fuller and the limits of Oikawa's English-language biography
Reliance on Richard Fuller's 1992 Shokan: Hirohito's Samurai limits the profile, while books awaiting translation offer scope for fuller studies.