Ogon & Platinum — Hikarimono (黄金 (Ōgon)／光りもの)

Single-colour metallic koi — gold, platinum and their kin — whose shine is the whole pattern.

Pattern diagram (schematic — checked against the JAS definition, not a photograph)
Ogon & Platinum — Hikarimono: Solid metallic colour with no markings; lustre even across the body and head.

Pattern (JAS-aligned)	Solid metallic colour with no markings; lustre even across the body and head.
Colours	Metallic gold (Yamabuki Ogon is yellow-gold), white-metallic platinum, orange and other solid metallic tones.
How to tell it	No pattern at all — one metallic colour, judged on shine, body and cleanliness of the head.

The variety in Japanese koi culture

Hikarimono, the shining ones, prove that pattern is not the only art in koi: a single flawless metallic colour, evenly lustrous from head to tail, has its own show presence. Yamabuki Ogon carries a lemon-gold shine, while the platinum form glows white-metallic and is often the fish visitors notice first in a pond at facilities such as Nishikigoi no Sato. With nothing to hide behind, body shape, skin quality and an unmarked head decide everything. The JAS framework places the metallic single colours within the Ogon and Hikarimono groupings used on the classification page of this guide.

Keeping notes on this page are limited to generally published principles about the variety in Japan. This page gives no diagnosis, no treatment and no prescription for an individual pond or fish. For a fish that looks unwell, contact a veterinarian or your local fisheries office.

Sources: Wikipedia (CC BY-SA — summary in our own words, credit only); All Japan Nishikigoi Promotion Association official; Ministry of Agriculture, Forestry and Fisheries (MAFF) and Finance Ministry trade statistics as published; Japanese Agricultural Standard (JAS) for nishikigoi variety names and definitions (2022); Niigata Prefecture, Ojiya City, Nagaoka City (Yamakoshi) and Nishikigoi no Sato official; Japan National Tourism Organization (JNTO) visitor statistics; USDA APHIS and Australian DAFF official import guidance. Checked 6 November 2026.