Hidden quiz
When prompted to INPUT (1 - 2) ? at the title, enter hiraganas えっちへんたい (ecchi hentai). This is done by, with most Japanese MSX, pushing KANA then 5, SHIFT+Z, A, ^, Y, Q, E. Each time you enter a character the screen flashes, the woman strips and the character is added to the password. After entering all the characters, push kana again and push either 1 or 2, then the quiz session starts that you push the SPACE bar after reading the question then type the answer.