Part of The Feudal Japanese Archery Weapons Classes, The Yumi was the more traditional of their “asymmetrical” Bow systems. Considered more elegant that the standard Archery Compound Classes, The Yumi was used by both mounted and foot Samurai. Development started around the 3rd Century A.D. - they were designed in part from those seen used in combat with The Chinese. The Bow Staff consisted of a single piece of treated (multiple layers of laminate), and shaped bamboo. Exceptionally long at 5 to 6 feet long, it was thought that this best suited a mounted fighter. Unusual in design, the Archery “grip” is positioned 2/3 of the way down the bottom (lower section) of the Bow Staff (differing greatly from the traditional European Longbow). This design increased the rearward tension (when pulled), and created even greater kinetic energy (and lessened vibration). This was needed with firing the overlong arrows (called “Ya” and ranging from 3 to 4.5 feet in some cases). A smaller “standard” Arrow shaft was also incorporated into usage. The Bow Staff length was effective for the mounted rider who needed to constantly switch sides (when firing at a full gallop). Bow Strings were made from hemp twine. These strings were not replaced until they actually broke. Exceptional care to The Yumi was needed (for it to retain it's shape). Much like The Katana, the Samurai place great care into the care of his Yumi. Due to the unusual size, Yumi are known as the World's Largest Bow.