Kojima said he owns every book in the I Spy series and specifically…

Kojima bought the Christmas installment of I Spy for his son without really knowing what it was because, when he opened it, the pictures transformed his surroundings into a world of silver. Father and son became hooked, solving the riddles together almost every night, and Kojima kept buying one volume after another until, by the beginning of the next year, they had collected the entire series; he jokingly warned against shameless copycat books.

What set I Spy apart for Kojima was that searches started from word clues rather than from a pictured model: the player had to abandon a preconceived notion of how, for example, a frog should look, accept shadows, reflections and objects that are cut off at the page edge, and mentally shift the scale within a toy-like world. The books did not include answers; instead they replaced that certainty with extra challenges and prompts to invent one’s own riddles, to be played alone or with a child.

Kojima joked that his aged eyes did not lessen the pleasure of I Spy because the battle is fought with the mind, not with visual acuity. Against search engines that hand you stores, movies, or books effortlessly, he defended the joy and catharsis of searching on your own and training the discernment needed to find something valuable.

“More than imitating movies directly, I would say it's that I try to recreate scenes in a cinematic way.”

Kojima said he loved the work of Teru Miyamoto and had read his novels exhaustively during his adolescence. While seeking escape in fanciful translated books, those novels helped him come to terms with his real, true-to-life self; he placed Kinshu as his favorite, followed by Haru no Yume and Ao ga Chiru.