The nagamaki was a long sword with a blade that could be 2 feet or more and a handle that about equal length to the blade.
The blade was single-edged and it could resemble a naginata blade, but the main difference in how the blades were mounted was that the handle (tsuka) of the nagamaki was not a simple wooden shaft as in the naginata; it was made more like a katana hilt Even the name “nagamaki” (“long wrapping”) is given by the tradition of handle wrapping. The nagamaki handle was wrapped with leather or silk cords in criss-crossed manner, very similar to the wrapping that is made on katana. The nagamaki is considered to be evolved from the extremely long nodachi or ōdachi swords that are described in fourteenth century literature and pictorial sources.
The length of blade varies on a nagamaki. However, the nagasa (blade length) most commonly fits the profile of a tachi or katana blade, which would be a blade of more than 2shaku (2 Shaku = 60.6 cm, roughly 2 feet) in length. While nagamaki means “long wrap” they have been found with no ito (wrapping cord) at all, which is very much like a longtachi handle. The tsukamaki (hilt wrap) is of even more importance when applied to the tsuka of a nagamaki. The cord helps to improve grip on the tsuka and also lends structural integrity to the wooden handle. Nagamaki found without hilt wrap usually had at least metal collars around the hilt where the tang is.
There are no solid rules governing the aspects of the make of the nagamaki. Unlike wakizashi, tantō, and katana, which have had history of strict measurements regarding thenagasa, and even the tsuka in some cases; the nagamaki varied in nagasa, nakago (tang) length, kissaki style, etc. Nagamaki presumably could have koshirae in a tachi or katana style as well as a nagamaki style, however there are examples of nagamaki with rather long nakago (tang), which could be fitted with a longer staff for a haft and effectively function as a naginata. Araki-ryū nagamaki is a heavy naginata over eight pounds of weight and eight feet long.
All traditional Japanese swords are fitted very snugly to their tsukas and held in place with a mekugi (bamboo peg) which is fit through a mekugi-ana (hole in the tang and hilt). This is actually quite a strong mount when done correctly, and allowed for easy dismount of the bare blade for maintenance or inspection. Katana most commonly had one singlemekugi, and nagamaki commonly have been found with two or more to account for the added leverage of a longer handle.
The way to hold a nagamaki is very specific. It is held with the two hands in a fixed position in the same way a katana is held. Unlike the naginata, the hands do not change when handling the weapon and the right hand was always the closest to the blade. While handling nagamaki fewer sliding actions on the handle are performed than are with thenaginata, where the entire length of the shaft is used. The nagamaki is designed for large sweeping and slicing strokes. Traditionally the Nagamaki was used as an infantry weapon. Warriors used the weapon against horsemen. Examples of real nagamaki can be seen today as nagamaki-naoshi, which are nagamaki blades re-shaped into swords.