Yumi

This article is about the Japanese bow. For other uses, see Yumi (disambiguation).

Japanese bows, arrows, and arrow-stand

Yumi bow names.

Yumi (弓) is the Japanese term for bows, and includes the longer daikyū (大弓) and the shorter hankyū (半弓) used in the practice of kyūdō, or Japanese archery.

The yumi is exceptionally tall, standing over two meters, and surpassing the height of the archer (ite, 射手). They are traditionally made by laminating bamboo, wood and leather, using techniques which have not changed for centuries, although some archers (particularly beginners) may use a synthetic yumi. The construction used may be a Japanese development of the laminated bows widely used for centuries across Northern Eurasia and in Jōmon times in Japan.

Shape

The yumi is asymmetric; According to All Nippon Kyudo Federation, the grip has to be positioned at about two-third the distance from the upper tip.

Yumi; world largest bow

But in actual fact, strictly speaking, it is positioned at about three-fifth.

And upper and lower curves differ. Several hypotheses have been offered for this asymmetric shape. Some believe it was designed for use on a horse, where the yumi could be moved from one side of the horse to the other with ease. But the grip position has emerged before bowing on a horse was widely spreaded .(refer to "Yabusame")

Others claim that asymmetry was needed to enable shooting from a kneeling position and yet another explanation is the characteristics of the wood from a time before laminating techniques. In case bow is made from a single wood, its modulus of elasticity are different between the part of treetop and the other side. Griping lower balances it.

And another, the hand holding the yumi experiences less vibration at this point. The point one-third and the point two-third the distance from the upper tip are the nodes. It makes bowyer easy to grip yumi after shoot a arrow.

String

The string (tsuru) of a yumi is traditionally made of hemp, although most modern archers will use strings made of synthetic materials such as Kevlar, which will last longer. Strings are usually not replaced until they break; this results in the yumi flexing in the direction opposite to the way it is drawn, and is considered beneficial to the health of the yumi. The nocking point on the string is built up through the application of hemp and glue to protect the string and to provide a thickness which helps hold the nock of the arrow in place while drawing the yumi.

Regard

Serious kyūdō practitioners treat the yumi with reverence, as pieces of great power, and as teachers with much to impart to the student (a yumi is said to hold within it part of the spirit of the person who made the yumi). A kyūdō student will never step over a yumi which lies on the ground (that would be considered disrespectful), and will typically treat a yumi as they themselves would wish to be treated (e.g. kept away from excessive heat or cold, kept dry, kept away from excesses of humidity or dryness, carried upright). It is also considered disrespectful to so much as touch another person's yumi without his/her permission; yumishi (yumi-maker) Kanjuro Shibata has said this is tantamount to touching someone else's spouse in a sexual manner.

Care

A bamboo yumi requires careful attention. Left unattended, the yumi can become out-of-shape and may eventually become unusable. The shape of a yumi will change through normal use and can be re-formed when needed through manual application of pressure, through shaping blocks, or by leaving it strung or unstrung when not in use.

The shape of the curves of a yumi is greatly affected by whether it is left strung or unstrung when not in use. The decision to leave a yumi strung or unstrung depends upon the current shape of the yumi. A yumi that is relatively flat when unstrung will usually be left unstrung when not in use (a yumi in this state is sometimes referred to as being 'tired'). A yumi that has excessive curvature when unstrung is typically left strung for a period of time in order to 'tame' the yumi.

A well cared-for yumi can last many generations, while the usable life of a mistreated yumi can be very short.

Bow lengths

Height of archer	Arrow length	Suggested bow length
< 150 cm	< 85 cm	Sansun-zume (212 cm)
150–165 cm	85–90 cm	Namisun (221 cm)
165–180 cm	90–100 cm	Nisun-nobi (227 cm)
180–195 cm	100–105 cm	Yonsun-nobi (233 cm)
195–205 cm	105–110 cm	Rokusun-nobi (239 cm)
> 205 cm	> 110 cm	Hassun-nobi (245 cm)

Yumi history

Time Period	Type of Bow	Bow Formation
Prehistoric	Maruki	Single piece of wood
c.800-900	Fusetake	Wood with bamboo front
c.1100	Sanmaiuchi	Wood with bamboo front and back
c.1300-1400	Shihochiku	Wood surrounded with bamboo
c.1550	Sanbonhigo (Higoyumi)	Three-piece bamboo laminate core, wooden sides, bamboo front and back
c.1600	Yohonhigo (Higoyumi)	Four-piece bamboo laminate core, wooden sides, bamboo front and back
c.1650	Gohonhigo (Higoyumi)	Five-piece bamboo (or bamboo and wood) laminate core, wooden sides, bamboo front and back
c.1971-Modern times	Glass fiber	Wooden laminate core, FRP front and back

The Korekawa bow, from the late Jōmon period which ended about 400 BCE, is laminated.

References

• Herrigel, Eugen (1999). Zen in the Art of Archery. Vintage. ISBN 0-375-70509-0.
• The Korekawa bow at Nara National Museum
• Michael, Henry N. (1958). "The Neolithic Age in Eastern Siberia". Transactions of the American Philosophical Society. New Series. Vol. 49, no. 2. Philadelphia: The American Philosophical Society (published April 1958). pp. 1–108. doi:10.2307/1005699. Retrieved 2008.02.13.. {{cite news}}: Check date values in: |accessdate= (help)