What Is Uguisu Green? Its Color Characteristics and the Origin of Its Name

Uguisu green, called uguisu-iro (鶯色) in Japanese, is a muted yellow-green named after the uguisu, a bird whose song is associated with spring. Rather than the bright green of fresh leaves, it is a subdued shade with yellowish, grayish, and slightly brownish tones. Published swatches vary, so choosing a specific digital color code matters when using the name on a website. This article explains the name and the bird behind it, compares two color references, and shows how to use uguisu green with readable text and buttons.

Uguisu-iro is a muted yellow-green named after the uguisu bird

The name uguisu-iro comes from the plumage of the uguisu, the Japanese bush warbler. Japanese color references classify it as a subdued or dull yellow-green. Its mix of green and yellow has an earthy, somewhat grayish appearance rather than the brightness of a vivid spring-green color. This distinction matters when choosing a swatch: a name associated with spring does not necessarily describe a pale or brilliant green.

The uguisu is well known for its “ho-hokekyo” song and is sometimes called the harutsugedori, or “bird that announces spring.” Its actual plumage is a relatively inconspicuous greenish brown. A brighter yellow-green bird seen near spring blossoms may instead be a mejiro, the Japanese white-eye. Although uguisu green is named for the bush warbler, the color name alone is not a reliable way to identify a real bird by its appearance.

There is also a related Japanese color name, uguisu-cha (鶯茶), often translated as an uguisu-like brown. Some reference books list it separately from uguisu green. Rather than treating the two names as necessarily identical, check which actual sample the reference or design is using.

Compare uguisu green swatches and try them on a website

The Japanese color site Genshoku Daijiten lists uguisu green as ■#928C36, while I-IRO gives ■#9D973B. The first has RGB values of red 146, green 140, and blue 54; the second is red 157, green 151, and blue 59. RGB describes screen colors using the red, green, and blue components of light. Both samples are olive-like, muted yellow-greens, with a contrast ratio of only about 1.15:1 between them. Their small difference in brightness is not enough to communicate a selection state through color alone. HEX is a six-digit hexadecimal code for specifying a web color; there is no single universally fixed HEX value for uguisu green.

Example 1: Use uguisu green for a large background. On a banner announcing a spring birdwatching event, use uguisu green ■#928C36 as the background and very dark green ■#10180F for the heading and short introduction. The text-to-background contrast ratio is about 5.20:1. A contrast ratio measures the difference in relative luminance between neighboring colors. For a “Register for the Birdwatching Event” button, use deep green ■#17362B with white ■#FFFFFF lettering, providing about 13.13:1 for the text. The button itself contrasts with the surrounding uguisu green ■#928C36 at about 3.77:1. Place the date and meeting location in a warm paper-colored ■#F9F6ED section with dark green ■#10180F text, which provides about 16.76:1.

Example 2: Reserve uguisu green for a small information label. On a longer bird-information page, make the main background warm paper ■#F9F6ED and set body text in very dark green ■#10180F at about 16.76:1. Fill only a label reading “About the Uguisu” with uguisu green ■#928C36 and use the dark green ■#10180F for its lettering, giving about 5.20:1. The label differs from the paper background by about 3.22:1. If you substitute the other uguisu green sample ■#9D973B, however, its contrast against the paper drops to about 2.81:1. Where the boundary must remain easy to identify, add an outline in very dark green ■#10180F and review the label after changing the swatch.

Check white text and do not rely on color names alone

White ■#FFFFFF text on the main uguisu green ■#928C36 has a contrast ratio of only about 3.48:1. That may meet the 3:1 requirement for qualifying large text, but it does not meet the 4.5:1 requirement for normal-size text. For smaller labels and longer descriptions, use very dark green ■#10180F at about 5.20:1 instead. The same dark green on the alternate uguisu sample ■#9D973B gives about 5.97:1.

Under WCAG 2.2 Level AA (the Web Content Accessibility Guidelines), normal text generally needs a contrast ratio of at least 4.5:1, and qualifying large text needs at least 3:1. Essential non-text cues, including some control outlines, may also need 3:1 against adjacent colors. Do not distinguish “Registration Open” from “Closed” using slight differences between uguisu green shades alone; include wording or another visible cue.

HueRoll allows HEX input and lets you check a selected color’s contrast against white or black. It cannot compare arbitrary pairs of custom colors or automatically determine AA or AAA compliance. Check the actual neighboring text, backgrounds, labels, and buttons separately when finalizing a design.