The wakizashi is essential in the basic equipment of the samurai warrior. Usually classified as a short sword, it is part of the pair of swords that is completed with the long sword. It measures between 30 and 60 centimeters, and is the only weapon from which the samurai never separated.
In the Edo era this pair of swords was considered the symbol of the samurai class, it brought prestige. They were transported introduced between the hakama and the obi on the left side; in fact, the wakizashi kanji (脇 差) mean to insert on the side
This clothing began to be used in the fourteenth century, when it replaced the tachi, larger. This change of customs obeys to the restriction imposed, by the government of the shogunato, to take swords of certain size in the places reserved to the aristocracy. In matches of this style, the long sword should be left in the entrance, while the short sword was allowed to always carry.
The wakizashi had been used very intensively in the great battles of the previous epochs, but in the peace that the Edo era brought, it stopped being so much a battle item, to become a weapon for self-defense. This means that the short sword, in itself, was also used by citizens who did not belong to the samurai class, to defend themselves in street duels or in disputes between bands.