Doitsu' is a koi that either: 1) has no scales at all; or 2) has scales only along the dorsal fin and maybe along the lateral line as well.
Lemon Kikokuryu 51cm (20")
Koi Types Chart http://www.pic2fly.com/
Doitsu Hariwake Koi
Hikarimoyo: Metallic koi that have more than one colour, but are not of Utsuri lineage
'Taisho Sanshoku', or 'sanke' is a koi that has a white body with red and black markings.
'Hikari Utsuri' is the metallic version of the Showa and Utsuri.