I've been seeing this fellow in the pages of "Japanese City Pop" for the past little while now and looking him up on YouTube, I was surprised to find quite a number of his songs represented there.
For a bit of background, Tatsuhiko Yamamoto（山本達彦）is a singer-songwriter who was born in Shinjuku Ward in Tokyo in 1954. As a child, he joined the chorus group which would later be known as the Tokyo Shonen Shojo Gassho Tai（東京少年少女合唱隊）, or as they are known in English, Little Singers of Tokyo; according to J-Wiki, the group did a tour of the United States and even appeared on the legendary "The Ed Sullivan Show" (still have very early memories of that program). In his university years, he got involved in a band called Orange for a few years until it disbanded in 1976 after which he started his solo career as a singer-songwriter.
I'm not sure what his Orange days were like but from what I've read in "Japanese City Pop" and viewed on YouTube, it looks like Yamamoto fully embraced his inner City Pop (in fact, his J-Wiki bio stated that he was once called The Young Noble of City Pop) starting from 1982 at least which was when he released "Last Good-Bye". It's a nice slice of nighttime City Pop with soul and the singer sounds a bit like fellow crooner Junichi Inagaki（稲垣潤一）in a slightly lower register. While he composed the song, Keisuke Yamakawa（山川啓介）provided the lyrics for the single which sold a little over 70,000 records and got as high as No. 40 on Oricon.
His J-Wiki bio also mentioned that although he has taken on that appearance of coolness in his concerts, he apparently has had the penchant for showing off his comic monomane skills in front of the audience. Nice.