Ichiban-yari (a group of spearmen or a person to spark a war) (一番槍)
The term Ichiban-yari refers to a warrior or group of warriors who engaged in combat using a spear. Although it was primarily used in reference to battles during the Sengoku Period (Period of Warring States) (Japan), in modern society it refers to the first person to distinguish themselves.
Summary
In battles during the Sengoku period (Japan), Ichiban-yari usually referred to the first warrior to defeat an enemy with a spear. Being that Ichiban-yari was considered proof of valor, it not only raised a soldier's reputation, but also made them eligible for Onsho (reward grants).
Military orders were often violated in attempts to receive the honor of Ichiban-yari. In a rare example, one of Ieyasu TOKUGAWA's vassals named Katsunari MIZUNO was punished for taking the position of Ichiban-yari in spite of his status as general (this was ostensibly due to the concern that if the general had died at an early stage of the battle, his army would have suffered a debacle, but he was also punished as a warning against being too self-assertive as a leader).
In addition to Ichiban-yari, there was also Ichiban-dachi (first sword).