Yari History . Early yari are believed to have been derived from Chinese spears , these " hoko yari " are thought to be from the Nara period ( 710 - 794 ) . , and while they were present in early Japan ' s history , the term " yari " appeared for the first time in written sources in 1334 but this type of spear did not become popular until the late 1400s . The original warfare of the bushi was not a thing for " commoners " ; it was a ritualized combat usually between two warriors who would challenge each other via horseback archery . However , the attempted Mongol invasions of Japan in 1274 and 1281 changed Japanese weaponry and warfare . The Mongol - employed Chinese and Korean footmen wielded long pikes , fought in tight formation , and moved in large units to stave off cavalry . Polearms ( including naginata and yari ) were of much greater military use than swords , due to their much greater range , their lesser weight per unit length ( though overall a polearm would be fairly hefty ) , and their great piercing ability . Swords in a full battle situation were therefore relegated to emergency sidearm status from the Heian through the Muromachi periods . Around the latter half of the sixteenth century , ashigaru holding pikes ( nagae yari ) with length of 4 . 5 to 6 . 5 m ( 15 to 20 feet ) became the main forces in armies . They formed lines , combined with arquebus iers and short spearmen . Pikemen formed two or three row of line , and were forced to move their pikes in unison under command . " Yari " eventually became more popular than the " yumi " ( bow ) as a weapon for the samurai , and foot troops ( " ashigaru " ) used them extensively as well . But by the Edo period the yari had fallen into disuse : with the greater emphasis on small - scale close quarters combat and the convenience of swords ( as opposed to long battlefield weapons ) , polearms and archery lost their practical value . During the peaceful Edo era , yari were still produced , sometimes even by good sword smiths , they existed as a ceremonial weapon and a samurai police weapon for most of this era . Description . Yari were characterized by a straight blade that could be anywhere from several centimeters , to 3 feet or more in length . The blades were made of the same steel ( " tamahagane " ) that traditional Japanese sword s and were forged with , and were very durable . Throughout history many variations of the straight yari blade were produced , often with protrusions on a central blade . Yari blades ( points ) often had an extremely long tang ( " " ) ; typically the " nagako " would be longer than the sharpened portion of the blade . The " nakago " protruded into a re - enforced hollow portion of the handle resulting in a very stiff shaft making it nearly impossible for the blade to fall or break off . The shaft came in many different lengths , widths and shapes ; made of hardwood and covered in lacquered bamboo strips , these came in oval , round , or polygonal cross section . These in turn were often wrapped in metal rings or wire , and affixed with a metal pommel on the butt end . Yari shafts were often decorated with inlays of metal or semiprecious materials such as brass pins , lacquer , or flakes of pearl . A sheath was also part of a complete yari . Variations of yari blades . Various types of yari points or blades existed . The most common blade was a straight , flat , design that resembles a straight - bladed double edged dagger . This type of blade could cut as well as stab and was sharpened like a razor edge . Though yari is a catchall for spear , it is usually distinguished between " kama yari " , which have additional horizontal blades , and simple " su yari " ( " choku - sō " ) or straight spears . Yari can also be distinguished by the types of blade cross section : the triangular sections were called " sankaku yari " and the diamond sections were called " " . Variations of yari shafts ( " nagaye or ebu " ) . A yari shaft can range in length from one meter to upwards of six meters ( 3 . 3 to 20 feet ) .