This category includes all Koi with shiny body but devoid of any markings. Hikari-muji are divided into "Yamabuki Ogon (with pure yellow, metallic sheen on the entire body)," "Platinum Ogon (with shining platinum color)," "Orange Ogon (with orange sheen)," "Kin Matsuba (literally 'golden pine needles,' for individual, glittering scales appearing like raised markings)", and "Gin Matsuba (literally 'silvery pine needles,' for glittering scales on the platinum ground which look like raised markings)," etc.
As they don't have any markings, the condition of luster and body conformation become the essential points for appreciation of Hikari-muji group. Excellent luster is the one which covers the whole body evenly. Generally, Koi of Hikari-muji group readily get used to humans. With hearty appetite, they tend to grow over-sized bellies. However, good shape body, covering from the head to breast and abdomen.