Blurred coloring - Ungensaishiki

...One of the coloring techniques used in decorative designs in architecture, painting, crafts, etc. Also written as 'Unjou'. It refers to painting the same color family in stages, moving from dark to light tones (or vice versa), without using a gradation method. Usually, the lightest (lightest) color is placed on the outside, and the colors gradually become darker (darker) toward the inside in two or three or more stages, but when the outside is dark and the colors gradually become lighter toward the inside, it is called 'Gyaku-Jou'. For example, blue-based 'Jou' is expressed with changes such as shirogun, ultramarine, and ultramarine + sumi....

*Some of the terminology explanations that refer to "Undertone Color" are listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…建築，絵画，工芸などの装飾文様における彩色技法のひとつ。暈繝彩色とも書く。同一系統の色彩の濃淡の変化を，ぼかしの方法によらず，濃い色調から淡い色調へ(あるいはその逆)段階式に区切りをつけながら塗ることをいう。普通，外側に最も明るい(淡い)色をおき，内側へしだいに暗く(濃く)2～3段，もしくはそれ以上に並べていくが，外側を暗色とし内側に向かってしだいに明色とする場合は逆繧繝と呼ぶ。例えば，青色系の繧繝では白群，群青，群青＋墨などの変化で表す。…

※「暈繝彩色」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報