Wakizashi were made with different zukuri shapes and sizes, and were generally thinner than katana. They very often had much less niku (literally 'meat' or 'flesh', the measure of how convex the edge is) and therefore cut softer targets much more aggressively than a katana. Its hilt is normally of a square shape but on rare occasion it had none.
A wakizashi was used as a Samurai's weapon when the Katana was unavailable. When entering a building, a samurai would leave his katana with a servant or page who would then let it rest on a rack called a katana-kake with the hilt pointing left so that it had to be removed with the left hand, passed to the right, then placed at the samurai's right, making it difficult to draw quickly, and reducing suspicion. However, the wakizashi would be worn at all times, and therefore, it made a Sidearm for the samurai (similar to a soldier's use of a pistol). The samurai would have worn it from the time they awoke to the time they went to sleep. In earlier periods, and especially during times of civil war, a tantō (dagger) was worn in place of a wakizashi. For particularly strong samurai like Miyamoto Musashi, the blade was sometimes used as an off hand weapon while the favored hand wielded the katana in order to fight with two weapons for maximum combat advantage. Shortly after his arrival, MacArthur ordered that all Japanese personnel give up their katana and wakizashi: seven tons of swords were confiscated and sent to San Francisco.