Biography
Yamato nadeshiko (やまとなでしこ or 大和撫子), a complicated Japanese aesthetic and cultural concept. Breaking the expression down: "Yamato" is one of the older (and thus fancier) and more poetic names for Japan and the Japanese people and culture, similar to the Latin "Albion" for the island of Great Britain and Irish "Hibernia"/"Erin" for Ireland; "Nadeshiko" is the Japanese name for Dianthus superbus, a wildflower found in the Japanese highlands that is related to the carnation (Dianthus caryophyllus).
Broadly speaking then, a yamato nadeshiko is a "flower of Nipponese womanhood": a woman with attributes that were considered desirable in the neo-Confucian Japan of the nineteenth century and beyond. The term was generally ascribed to noble women with traditional upbringings, but after the formal abolishment of the caste system it passed into wider use among the new "middle classes". Being a yamato nadeshiko revolved around the Confucian concepts of Feudal Loyalty and Filial Piety, which in the latest wave of Confucian revival meant acting for the benefit of one's family and obeying and assisting authority figures (father, husband, sometimes father-in-law or older brothers, as well as older and/or more respected females). Virtues include(d) loyalty, domestic ability, wisdom, maturity, and humility.
Don't let her gentle demeanor fool you; the nadeshiko is a wildflower at heart. A properly done yamato nadeshiko will show a subtle, but definitely present, touch of iron in that she is unwilling to let circumstances hurt the ones she cares about or distract her from her goals or missions. This is often accomplished so subtly that the target isn't certain how things got redirected — a subtle influence of Politeness Judo if you will. Older yamato nadeshiko are better at this, while a younger one will make up for it in determination — especially when it comes to the man she loves. Tropes Are Tools, after all.
A poorly done yamato nadeshiko, however, will turn out like an Extreme Doormat. They are silent and submissive without the inner strength of a true yamato nadeshiko. This is a common stereotype of East Asian women in Western fiction and is often referred to derisively as the China Doll stereotype.
With some notable exceptions, yamato nadeshiko will be of medium height, willowy, modestly endowed, and good-looking without being too beautiful or too cute; they will have pale skin and long dark hair with full, straight bangs and sidelocks. They'll dress in feminine fashions: skirts, blouses, low-heeled shoes, lace, ribbons and simple hair ornaments. The other option is the impeccable ladylike style for adults. A kimono is likely to be worn by a nadeshiko brought up in the good old Kyoto style. Some may wear jewelry and make-up, but not too much. Their voices will often be as gentle, calm, and warm as melted butter. Large, rounded eyes are always a good bet. It is not unusual for geisha to be a yamato nadeshiko. Will also be likely to say Ara ara ("Oh My") as a Verbal Tic to indicate calm surprise.
Sometimes, these ladies will also know self-defense, even if they would rather not fight if it can be avoided. This makes sense as many nadeshiko came from samurai clans and thus were trained in fighting, so they could defend their homes whenever the males were absent. If that's the case, they'll be very graceful and effective in the battlefield, and they're likely to be White Magician Girls or Barrier Warriors. If they're neither, they'll likely use polearms, lances (specifically naginata which daughters of samurai families were traditionally trained in and included in their dowry) or bow/arrows, and maybe even small tantou daggers that may be hidden in their clothes.
These characters pop up a lot in Magical Girlfriend series (usually as the one who will win the male lead's heart) and as the "Betty" in Betty and Veronica Love Triangles. They tend to be passive, putting them in danger of becoming Satellite Characters for more "interesting" people, as well as a target of bashing from fans who prefer more active love interests such as Tsundere.
Expect her name to end in "-ko" [子] or "-bi", "-mi" [美], which mean "child" and "beauty", respectively.Protip Less subtle examples might even use Nadeshiko for the Meaningful Name factor.
You will sometimes find males who fit in the yamato nadeshiko role, personality and/or looks-wise (like Japan in Hetalia: Axis Powers, obviously), but this is still rare. Sometimes, there's also overlap with the Samurai, since Japanese noblewomen that held this occupation were known as onna-musha or onna-bugeisha. This trope is commonly used in the portrayal of a Patient Childhood Love Interest character's personality.
More information on this concept can be found in the sci.lang.japan FAQ.
Compare Moe, another standard of idealised Japanese beauty, but with less emphasis on maturity and more on protectiveness, youthfulness and vulnerability. Compare and contrast Geisha, who are expected to be outspoken, social and intellectually equal to men.
For Western equivalents, see also "angel in the house," English Rose and the Proper Lady. Compare Silk Hiding Steel, Spirited Young Lady, Princess Classic, Southern Belle (her US counterpart), The Ingenue.
For subversions, see Stepford Smiler and Yandere for a girl who seems to be a Yamato Nadeshiko but hides a far more unstable psyche.
Note: This trope is for the Japanese archetype in particular and the Eastern Asian archetype in general. For the Western/European archetype, see Proper Lady. For a general 'proper on the outside, powerful on the inside' woman, use Silk Hiding Steel. For tropes describing homemakers and housewives in general, use Housewife. To describe 'innocence' or 'gentleness', use The Ingenue. Polite or friendliness can be covered by Nice Girl. For a person whose niceness belies danger/effectiveness, use Beware the Nice Ones. General girliness is covered by Girly Girl.