Chage was responsible for writing and composing "Futari no Ai Land" with Goro Matsui（松井五郎） (who was usually associated with Anzen Chitai) helping out on lyrical duties. Another cross-cultural pun was born within the words here; Chage had wanted to insert the word "coconuts", but someone told him that there were no coconut trees in Okinawa (the song was used for the 1984 JAL Okinawa campaign commercials). Rather obsessed with keeping that coconut in there, Chage somewhat sarcastically (according to J-Wiki) created a rather clever pun by placing the homophonic lyric "Koko natsu" as in "Koko wa natsu"(ここは夏...Here is summer!) Necessity is the mother of invention, indeed.
"Futari no Ai Land" came out in April 1984 and peaked at No. 3. Selling just under 440,000 records, it became the song of the summer for that year. For the entire year, it was the 16th-ranked song.
And here is the aforementioned commercial.