I've listed some common male names below. The nuance will change depending on which one you use. A few Japanese males were traditionally named according to the sequence they where born in. (An example is "Ichiro" of the Seattle Mariners: his name typically indicates a first born son).

Taro (akin to "Joe" or "John" as in "Joe Smith" or "John Doe")
Jun
Junichiro (very common. Current prime minister Koizumi's first name)
Hiroshi
Hitoshi

Another common pattern is to make a name using 2 characters with 2 sylables each, generating such names as:
Toshifumi
Masahito
Terutomo
Hiroaki
Akihito
Naruyuki

You can probably find some examples online combing thru articles in the English language versions of major Japanese newspapers. Try the Asahi-shinbun and Yomiuri.

Good luck.

Koru may be 'Toru', a very common Japanese name for boys. I have never heard of any men named Koru.
There are other common boys' names - 'Wataru', 'Ichiro', 'Taro', 'Yutaka', and so on.

I am a native Japanese; born and grew up in Osaka, Japan, and hope this could give you some idea,
Noriko