The decision to leak classified footage of the Japan Coast Guard's run-in last year with a Chinese trawler wasn't an easy one to make, but ended up being a matter of civic duty, former coast guardsman Masaharu Isshiki says in his new book on the Senkaku Islands clash, in which he wasn't a participant.

"Some people praise me and call me a hero, but I am not that noble of a person," Isshiki says in "Nanika no tame ni — sengoku38 no Kokuhaku" ("For Something — The Confession of sengoku38"), a copy of which was obtained by The Japan Times.

"Rather, I am just a person, trying to become someone noteworthy. . . . I did what was a matter of course as a Japanese citizen," he said.