Wooo~ How natsukashii! I used to hear this a fair bit years ago through a BEST compilation, "BEST Remix" by 1986 Omega Tribe（1986オメガトライブ）. But I got to hear it again last night while rummaging in JTM's vast collection of music.
This is Carlos Toshiki（カルロス・トシキ）crooning "Night Child" which was originally on 1986 Omega Tribe's first album under their new configuration without the original vocalist, Kiyotaka Sugiyama（杉山清貴）, "Navigator" from July 1986. As the title would indicate, this would be the ideal ballad to hear during a romantic evening in Hawaii: candlelight, balcony, palm trees, lapping waves on the shoreline, the whole 9 yards.
Written by Asako Yano（矢野朝子）and composed by Omega Tribe keyboardist Toshitsugu Nishihara（西原俊次）, "Night Child" is as much about the band's representative sound which is kinda like the yang to TUBE's yin. I still don't consider myself an expert on the band throughout its name changes, but even so, one of the points of comparison for me involves vocalists Sugiyama and Toshiki. I've always considered Omega Tribe to be one of the mellower bands in Japanese pop history but there was something even creamier about Toshiki's voice which makes it a great fit when it comes to those ballads.
"Navigator" itself went all the way up to No. 2 on the Oricon weeklies and achieved No. 20 on the 1986 yearly rankings. The album also has another Omega Tribe classic in "Kimi wa 1000%"（君は１０００％）.