Hosonaga is a type of ubugi (swaddling clothes) of the Heian period with a shape similar to kariginu (a type of ancient kimono). In the Edo period, it became a customary practice for the imperial court to send it as one of the congratulatory gifts for the Tokugawa clan when a heir was born into the clan. It is also called ubugi-hosonaga.
Also hosonaga is a sort of clothing worn by middle Heian period women.
Its configuration is unknown and thus it is called a 'mysterious costume.'
Yet other hosonaga were worn as an undergarment for adult men, around the 10th century. Its existence is known through Chapter Fukiage of the "Utsubo monogatari" (The Tale of the Hollow Tree) and so on.
There is an example of ketteki no ho (open sleeve seams outer robe) for court kids described as 'hosonaga ho,' and so on, in historical documents, the appellation 'hosonaga' is applied for many different sort of clothing.
Hosonaga often appeared in Heian literature as a 'garment for ladies of a high rank.'
Although it is generally said that hosonaga is 'a kimono worn by a young lady,' there are examples found here and there in literature of women over 30 wearing hosonaga, so the common idea is doubtful.
And 'Hosonaga' is often used as a gift.
After the Kamakura period, however, it was gradually not worn and was abandoned. Later during the Sengoku Period (Period of Warring States) (Japan), the reality of hosonaga could not be completely understood due to the collapse of the society of court nobles. While the Takakura family initiated a book, "Various costume" of the late Kamakura period, specifications of Women's hosonaga and baby clothes hosonaga is explained differently, in the "Genchu saihisho" (Secret notes on the Tale of Genji) which describes annotations on the tale, compiled by Kawachi side (the family of MINAMOTO no Chikayuki and others who worked actively on the research of "Genji Monogatari" (the Tale of Genji) mainly in Kamakura) of the same age, there was already found a mixture of baby swaddling hosonaga and the female garment hosonaga.
In the Edo period, with the re-establishment of Yusoku kojitsu (court and samurai rules of ceremony and etiquette), hosonaga was revived as a full dress for ladies of court nobles to wear at the time of 'Hakamagi ceremony.'
The type revived has no uchiki (ordinary kimono) and the sides are seamed. At the imperial family of today, royal princess and the queen wear this type of hosonaga when they perform the 'hakamagi no gishiki' ceremony.
Today, only the under age girls of the royal family wear women's hosonaga, and hosonaga as an undergarment for men or baby swaddling hosonaga are not used.
Hosonaga for Women
As for the hosonaga for women, it is only written that 'there is no high neck of that kinu (clothes)' in a costume guide book, "Masasuke Shozokusho" (Masasuke's Notes on Court Costume) and thus it is barely known that hosonaga is not a sokutai sort of closed collar costume. Kinu' usually means that men's uchiginu (inner garment) or women's kasane-uchiki (a series of brightly colored unlined robes), thus kinu might be a so-called tarikubi (a type of kimono collar, hang-down collar) but there is no reliable evidence. There are almost no historical materials other than this description, other construction of hosonaga is not known.
The assertion presented today is that:
A kimono with sides that are not seamed and mae-migoro (front main panel) and ushiro-migoro (back main panel) are separated, and the right and the left of the ushiro-migoro is stitched at the back and is long. Sides are not seamed and migoro (main panel) are all separated parts and they are stitched around the sleeves. And it is similar to kazami, a costume that girls wore during the Heian period. And so on.
Further, although, too extreme speculation that:
Hosonaga are clothes made only for use as gifts and it was not in fact worn. There is also other arguments like the above. However, because the actual way of wearing hosonaga seen in "Genji Monogatari" (the Tale of Genji) might have been based on fact, it is reasonable to think hosonaga was worn by women including adults by layering with many garments including uchiki and sometimes with mo. Though stories about wearing hosonaga are also seen in archaistic tales such as the "Iwashimizu Monogatari" (Tale of Iwashimizu) written during the Kamakura period, it is thought that it may have only been described to create the atmosphere of the ancient times.
In the meantime, although the costume of a lady depicted in the chapter one of the roll of The Bell Cricket in 'Genji monogatari emaki' (the Illustrated Handscroll of the Tale of Genji) (in The Gotoh Museum) used to be thought as 'hosonaga' and it was an example of the shape of the clothes whereby the hem was separated, it turned out recently to be 'uchigi sugata with mo' and not hosonaga through reconstructing and reproducing work of the rolls based on scientific research ("Yomigaeru Genji Monogatari Emaki" (Reviving Illustrated Handscroll of the Tale of Genji, NHK Publishing). And it is surmised through a column of a pre-war magazine called 'Fuzokushi Kenkyu' (Study of folklore history) that the idea to reproduce hosonaga assimilated to kazami began with the misconception of a picture of a girl in kazami style on "Shoan Gosechi Emaki" (picture scroll of Shoan gosechi-e (annual court ceremony of girls music)) as hosonaga style.
Women's hosonaga in modern times is a formal costume of high and noble Emperor's daughters when they were girls, and the form is similar to uchiki as the aforementioned tailored without a gusset, and it is common to insert nakabe (lining cloth attached between the outer material) like kochigi. In the Daisho-ji Temple, there is a hosonaga of the Emperor Kokaku's daughter which is slim-fit and it has a length is long. There is a hosonaga descendent of the Arisugawanomiya family in the Kyoto National Museum, and the form of it is nearly the same as that of the aforementioned emperor's daughter's, however, the length is shorter and it seems there is a distinction of hosonaga between the hosonaga of the imperial family and that of hereditary prince's household.
Girls' hosonaga in the modern times are clad with layered hitoe (unlined garment) in dark colors (red bean color) and hakama in dark colors, and not layered with itsutsu-ginu (5-layer garment). As textile of hitoe is included in Takakurake choshin hikae gire(Takakura family order sample cloths), the possession of Kokugakuin University, it is with smaller saiwai bishi (a pattern of cloth) than that for adult women. In the Yamashina family, many textiles for hosonaga are matsushige (moegi color for omote (outside cloth), murasaki (purple) for ura (background cloth), koiro color for nakabe or kurenai (deep red) for ura, usu kurenai (light red) for nakabe, an ordered arabesque pattern of white pine for the outside cloth). Although this form is followed even in the modern times, the degree of freedom on irome (color combinations) has increased and the Emperor Showa's daughters' hosonaga are ordered with many kasane (a sort of layered garment), and also after the war, that of Princess Sugako is of double fabrics of arabesque pattern of white pine upper design on red hexagonal pattern base, and that of Princess Mako is of double fabrics with a white chrysanthemum on a branch woven with plural colored threads on red hexagonal pattern base, and that of Princess Aiko is of double fabrics of circles of white chrysanthemums on a branch (usu kurenai for nakabe, moegi for ura (background), a combination of colors) woven with plural colored threads on kurenai mie tasukiji (a sort of pattern) background.
Baby Swaddling Hosonaga
Hosonaga used as baby clothes are depicted in the 'Murasaki Shikibu Nikki Emaki' (illustrated scroll of the Lady Murasaki's Diary) produced in the early Kamakura period. According to the scroll, there are no end sleeves and the hem of front panel and back panel, which is not stitched with ketteki (open sleeve seams), is split and looks like strips. In the literature, hosonaga and casing of it with detailed description are shown in the column of the birth of the Emperor Gofushimi's Princess Junshi in "Entairyaku"(Diary of Kinkata TOIN). Baby hosonaga clothing given from the court to the Tokugawa family in modern times was based on this book as a reference.
Baby hosonaga clothing in modern times is aya (twill weave, pattern of diagonal stripes) with white kikkomon (turtle shell design) (without second dewing) like kariginu (loose short jacket with abbreviated sleeves). The collar is banryo (round neck) but there is no kagero (part to fix clothes) and long cords are attached to the center back of the collar and the end of uwamae (where okagero is attached in case of kariginu) like suikan (the dress of upper class children). These cords are made of two pairs of cords twisted clockwise and anti-clockwise, and tied in a ninamusubi (a type of knot) like cords of women's hiogi (a sort of fan) and are suspended long. Sides are of ketteki (open sleeve seams) and the length of the clothes is rather long. It looks like a suikan, however, the sleeve is hitono (unit of width of cloth is 33 to 36 cm) and there are no end sleeves. Hitoe with twill of white dense diamonds (a pattern used as the back of karaginu) is layered.
In the meantime, there are size charts in a book from a descendent of the Takakura family, "Shozoku Sunpo Shinhisho" (selection of costume size secrets) (in 1400). A small cloth called 'katano hira hira' (flaps on the shoulders) is attached to the back of banryo collar (perhaps, the cloth is a surplus made when the collar was cut out) and semamori nui (back sewn as a charm) is made from the cloth. The long cords attached to the collar are folded at the center and kagero is made there and both ends are suspended long and made into a ninamusubi (a sort of decorative knot). In the above the ninamusubi, letter with crane and pine tree are made with colored threads. And the sides are seamed. Colored textiles are permitted, however, it is said that the ninamusubi knot is limited to white.
Usually, hosonaga given away by the Tokugawa shogunate was ordered by Yamashina family based on the entry of "Entairyaku" as aforementioned, there were cases whereby the Takakura family ordered a different specification based on this "Sunpo Shinhisho" from 1818 to 1829. While irome (color combination or design) of hosonaga the Yamashina family ordered was limited to kikkomon, what Takakura family ordered was moegi aoidachi yumon with beni hiraginu line and the white ninamusubi knot were pine tree and cranes expressed with a stitched flower knot.
Probably, the costumes described in "Entairyaku" and "Sunpo Shinpisho" were similar kind and small differences were made when the details were recorded due to differences from the point of view of those observing, and two different restored version of hosonaga were made as a result. Further, as for baby swaddling hosonaga, there seems to be no difference between those for boys and girls.