An important part of a Japanese army was its spearmen. They gave defensive and offensive support for all the other elements but they had to be well trained and disciplined to be used effectively.

The spears carried by ashigaru were identical to those carried by the samurai and were wielded in the same way. However, by about 1530 the ashigaru spear lengthened to resemble something closer to a pike and was called a nagae yari or long-shafted spear. The length of the spear was usually three ken with one ken equal to about 1.6 metres, changing later to 1.8 metres; the length often varied from clan to clan, Oda Nobunaga's spearmen apparently carried spears 5.6 metres long. Now the ashigaru were trained to fight as a group and form up in several ranks while the samurai indulged in their pursuit of single combat and duels with worthy foes. The nagae yari consisted of an inner core of hardwood (usually oak) with a layer of bamboo laminated onto its surface. For protection against inclement weather the entire length of the shaft was lacquered.

Ashigaru spearmen had to be well trained and disciplined because the huge length of their spears could be just as dangerous to their own side as that of the enemy if used incorrectly. Some form of pike drill existed according to the Zohyo Monogatari, the book written in 1649 about ashigaru warfare. Ashigaru spearmen were to fight in a coordinated formation with the points of their nagae yari moving together. The author then states that the spearmen should 'line up in one rank three shaku apart, not thrusting but at the ready in a large row to hit the enemy. When facing an attack by horsemen line up in one rank kneeling, lie spear down and wait. When contact is imminent lift up the spear head into the area of the horse's breast. When the point pierces the skin hold onto it! Whether you are cutting at men and horses, it may be that you will feel you are being forced to pull out the spear, and it is a general rule to stand fast to the bitter end and not throw into disorder the collaborative actions. After you have driven the enemy back, to pursue for about one cho is sufficient'. 

Although the spearmen fought in coordinated units they never employed the rigid formations used by the famous Swiss pikemen, which for the battle of Fornovo in 1495 packed 3,000 pikemen into a unit covering an area of just sixty metres. Ashigaru spearmen liked slightly looser formations so that defence could quickly turn into offence. Some illustrations show spearmen forming a hedge behind the arquebusiers to protect them.

Further Reading

Warriors of Medieval Japan - Stephen Turnbull