I actually have two questions to post for people knoweldgeable in ninjutsu.
1. do any of the ninjutsu systems teach kodachi sword techniques?
Within the Kukishinden Ryu there are 3 techniques for use of the Kodachi against Tachi. They are Hicho no Ken (Sword of the Flying Bird), which is a technique against a cut from your right, Shishi Geki (Turn Around, Enter and Stab), a technique against a cut from your left, and Juji no Ken (Number 10, or Cross, Sword) against a downward cut.
The kamae for the weapon are taken from (or shared with) the kamae for Jutte: Muso no Kamae/Kagete no Kamae, Suicho no Kamae/Mizu Tori no Kamae (different readings of the same kanji, if you notice...), Ichi no Kamae, Seigan no Kamae, and Ten no Kamae.
Within the Kukishinden Ryu, the type of Kodachi used is a true "small tachi". Although it has a short blade, usually around 18 - 22 inches long, it features a long tsuka (around 12 - 14 inches), and is worn slung edge down from the hip. The longer handle allows a greater degree of leverage, which helps a great deal against an armoured opponent, providing, of course, a two-handed grip if required. This weapon should be thought of as a secondary weapon on the battlefield, used after your main weapon has been lost or broken. As a result, it is has the only sword-drawing kata within the Kukishinden Ryu proper (the rest I have seen are variations on principles in various kata from the Bikenjutsu section).
This type of sword is a good way to date the system, by the way. It was a very rare sword, and only featured in a handful of arts. Add to that the fact that this style of short sword was only known to have been commonly used during the Nambokucho Jidai (Period of Northern and Southern Courts, approx. 1332 - 1368), a very short period of time.
The Takagi Yoshin Ryu has a number of techniques as well, though. It is not commonly taught within Bujinkan schools, nor indeed any Ninjutsu schools that I have yet come across (other than when I taught it in our ones, of course...).
In Takagi Ryu, the techniques come under the title Kodachi Irimi, or Entering to the Body with a Short Sword, and teach 5 kata, as well as a section of basic cuts and kamae. The kata are: Ran Getsu (Chaotic Moon), Itteki (Single Enemy), Shisha Gumi (Messenger Group), Nito (Sun Sword), and Getto (Moon Sword). They are all evasive cutting techniques, and can be applied against a variety of attacks, but are most commonly taught against Shomen Giri type cuts or straight thrusts.
The Kodachi used in Takagi Ryu is a typical Wakizashi/Shoto short sword as is found in a Daisho pairing.
2. I have heard arguements that are both in favor of and opposed to the ninja-to being an actual historical weapon. Is it possible that kodachi would have been used historically instead of the hollywood ninja sword? Could they actaully somehow be one in the same?
As stated, it depends on what you are refering to as a Ninja-to. If you are refering to the sword used by the Togakure Ryu, then there may have indeed been some influence due to the locations of the few schools that used the Kukishinden-style configuration, but is still unlikely. Remember, there are a few key differences between the short sword I described above and the blade used in Togakure Ryu.
The Togakure Ryu sword and the Kukishinden Ryu Kodachi share similar dimensions, however, the Togakure Ryu sword had a slightly shorter tsuka, and a very slightly longer blade. It also had a full-size saya (with typical koshirae mountings - kurigata, sageo [although this was twice the length of most katana sageo], etc, rather than the Kodachi's typical Tachi-style mountings), and was worn edge up in the obi, rather than edge down hanging from the waist.
The techniques can be explored with both, though, and really should be if you are interested in these types of weapons. And, of course, if you have access to one or the other, they can serve in each others place quite easily.
your thoughts please
