The observations, descriptions, and conceptual models presented in this archive (Hiramasa Studies) are based on real-world experience in offshore Japan. This page clarifies the origin of the information by outlining the author's position, field of activity, and the basis of the primary source material.
Profile
Keiji Matsumoto | Born in 1974. Based in Fukuoka, Japan. He is the captain of STINGRAY, a fishing charter operating mainly in the Genkai Sea, Japan and the Goto Islands, Japan, guiding anglers primarily in Yellowtail Kingfish casting. He spends approximately 140 days at sea each year and guides a total of around 1,000 anglers annually.
Observation Methods and Primary Source Integrity
As a scuba diver, the author regularly dives in the Genkai Sea, Japan, observing fish behavior, underwater structure, currents, and feeding activity firsthand. Many of the descriptions in this archive regarding behavior patterns and feeding structures are based not only on practical experience in navigation and guide work, but also on the accumulated record of these underwater observations.
Media and Research Collaboration
Through cooperation on reporting and visual material related to the natural environment and marine conditions of the Genkai Sea, Japan, the author has contributed to NHK and commercial television programs. He is a former television director and continues to write for magazine media and other publications, remaining engaged in both field practice and the work of documentation and communication.
Position Within This Archive
The classifications, conceptual models, and structural organization presented in this archive are built upon practical experience accumulated through navigation, guide work, underwater observation, and field-based reporting. However, they are not intended to replace formal academic classification or established theory, but are presented as conceptual models for deepening practical understanding in the field.
Update History
- January 2026: First edition published