How to identify Doitsu
- Smooth skin with few regular scales.
- Mirror scales may run along the dorsal line or lateral line.
- Can appear as Doitsu Kohaku, Doitsu Sanke, Shusui, and many other forms.
Quality points
- Scale rows should be neat and intentional, not messy.
- Smooth skin makes scars, uneven color, and body faults easier to see.
- The fish still needs the correct pattern and quality for its base variety.
Common comparison
Doitsu is a trait, while Shusui is a variety that combines Doitsu scale type with Asagi ancestry and color placement.
| Look first at | Good sign | Beginner caution |
|---|---|---|
| Body | Balanced frame, smooth swimming, no deformity. | Do not let rare color hide weak conformation. |
| Skin and color | Clean, readable, and consistent for the variety. | Muddy color usually becomes more distracting with size. |
| Scale or luster trait | Even rows, sparkle, reticulation, or metallic quality depending on the group. | Random patches, dull fins, or broken scale rows reduce impression. |
Sources and editorial note
This page follows the variety structure used by Japanese koi references and the book notes in the My Koi Garden research library, especially the distinction between true variety groups and cross-cutting traits such as Doitsu and Gin Rin. Photos are limited to real images with source and license notes.