In the game's instruction manual, there is an encrypted five-character long code (apparently given to Takamaru by a spy) that reveals the weak point of the game's final boss. The cypher is Japanese Morse code using a combination of hiragana and kanji, and can be deciphered by replacing the hiragana with short vowels, and the kanji with long vowels. The correct answer is Spoiler:"くちのなか" ("kuchi no naka"), or "inside the mouth". In the first printing of Japanese publisher Tokuma Shoten's guidebook however, there was a typo in their copy of the code, resulting in this incorrect answer: Spoiler:"くちのやか" ("kuchi no yaka"). Three months after the game's release, Tokuma Shoten issued an apology in their publication "Family Computer Magazine", stating that the error had been corrected in the second printing of the guidebook onwards; they also included an explanation on how to solve it along with a guide to Japanese Morse code.