A Substitution Cipher in Chinese for Kids

I got a Chinese translation of a children's book that I mentioned when I reported a Korean version in March. I have been interested to know how the substitution table for Japanese syllabary is rendered in Chinese.

The Chinese language is written with thousands of Chinese characters, so unlike European languages with twenty or so letters or Japanese with some fifty kana, a substitution cipher is not feasible.

The book is Yutaka Hara, Kaiketsu Zorori, vol.11 ("Kaiketsu Zorori and the Mysterious Aliens") (Japanese: かいけつゾロリのなぞのうちゅうじん, traditional Chinese: 怪傑佐羅力 神秘的外星人). As expected, the substitution cipher is not based on Chinese characters but relies on the pinyin transcription of the characters. For example, the character 怪 is transcribed as g-u-ai in pinyin and (graphic) symbols for "g", "u", and "ai" are used to encrypt this character.