Cavalry was a military force formed by soldiers mounting on horseback, armed with swords, spears, and guns. Mounted soldiers had the advantages of high speed and great impact over their opponents on foot.
In the Medieval ｐeriod, only a person of high rank (samurai or knight) was able to join cavalry. Today, it almost lost its original function and became one of the features of ceremony. The police cavalry often patrol the city even now.
(In England and other countries)
After the ancient Japanese military system based on the Ritsuryo codes was replaced with the Kokuga forces system (provincial forces system), the term "Japanese cavalry" was used to refer to troops composed of units of mounted warriors, which amounted to a major military force, and their attendants (known as Jusotsu [officer's servants] or Buke hokonin [servants to samurai families] depending on the times). Until the emergence of ashigaru (foot soldiers) as combat personnel, it was generally accepted that official battles were basically conducted only by cavalry of samurai groups.
After the Sengoku period (Japan), when ashigaru began to be recognized as a new fighting force, the military system of Sengoku daimyo (Japanese territorial lord in the Sengoku peiord) shifted to that in which defense was regarded as a fundamental. Under these circumstances, the main duty of the cavalry as a defense force was to break through the front-line of ashigaru troops or to launch counterattacks against the opponent's ashigaru troops. Cavalry deployed for a defence force unit was composed of twenty to fifty horsemen; each horseman received an annual stipend of about 200 to 300 koku. In principle, each samurai paid his own expenses during the military service; his attendants (Buke hokonin) accompanying him were mostly rearguard supporters such as spear carriers or provision transporters except young samurai who served to protect him (one to two persons for each horseman).
Speaking of cavalry, the one that belonged to Shingen TAKEDA in the Kai Province during the Sengoku period was famous because of following reasons; the imperial pastures were established in the Kai and Shinano Provinces from ancient times, so there were many people who excelled in handling horses, and also many places for breeding horses; these areas had an image symbolized by the legend of a black horse of Kai; the horses bred in these areas showed high mobile ability in mountainous regions.
In the Heian period, shooting arrows on horseback was the main battle style of mounted warriors; after the Jisho-Juei Civil War, a new battle style appeared, in which a mounted warrior crushed into the enemy together with his horse, wrestled the enemy on horseback, killed the enemy by thowing him off from the horse.
Even until the Kamakura period, shooting arrows on horseback as typified in Yabusame (horseback archery) was the main style; from the late Kamakura period to the Muromachi period, this trend was accelerated due to the emergence of villains and armed peasants, and the battle style of mounted warriors shifted to the use of cutting weapons such as a long sword or a Japanese halberd. The style of a body-armor also shifted from Oyoroi (heavy armor) to Haramaki (a breast protection); a shallow saddle was more used than a deep one. When the Sengoku period started, spears introduced around the same time became the main weapon used by mounted warriors, and also listed as must-have items for a military service. However, since each samurai paid his own expences during the military service as mentioned before, the war outfit was almost left to the discretion of individuals; each samurai used various arms such as a bow, a gun, a spear or even a Japanese halberd carried by Buke hokonin.
In addition, unlike other arms, a Japanese sword was consistently worn in person from the Heian period mainly to show social status, and was regarded as a supplementary outfit for practical purposes.
(It does not mean that nobody used a Japanese sword as a main weapon.)
Initially, mounted warriors in the Sengoku period seemed to rush at the enemy's position by riding on horseback.
(For that occasion, young samurai, who followed close behind mounted warriors, probably caught up with them easily because the distance to the enemy was only 100 meters in consideration of shooting range of a matchlock gun.)
However, with the increase of ashigaru and the emergence of its military strategy against cavalry, rushing at the enemy's position on foot by dismounting from the horse became common first in the western part of Japan, and later throughout the country.
(Aming at horses was considered very important in both Yaribusuma [a line of long spears held ready to attack] and shooting by musket troops against mounted warriors.)
However, back from the Heian period, mounted warriors performed land battle when necessary; after land battle became common, they fought from horseback whenever occasion arose, and responded flexibly to the enemy's strategy.