Musō Shinden ryū (夢想神伝流) is a branch of the discipline iaido.
The art can be traced back to the originator of iaido, a samurai named Hayashizaki Jinsuke Minamoto no Shigenobu (1549-1621), in some traditions known as Hōjō Jinsuke Shigenobu. Many schools of swordsmanship developed from Hayashizaki's teaching, including Tamiya Ryu and Muso Jikiden Eishin Ryu. In the 18th century the school of Muso Jikiden Eishin Ryu split into two factions with rival soke (head masters). The Shinomura branch was the one that evolved into Muso Shinden Ryu. Nakayama Hakudo (1869 - 1958) became the soke of the Shinomura branch and revised the curriculum. He laid out a plan of study having students pass through Shoden (entry level), Chuden (middle level), and two sets of Okuden (inner level). In addition to the revised curriculum he also modified some techniques (for example the noto is now done level rather than at an angle). Some argue that many of these changes were made because of Nakayama's experience with other martial arts since he was highly ranked in other schools of kenjutsu and jodo. An example is how noto was changed to the noto of Shindo Munen Ryu Kenjutsu as done in its Suwari waza and Okuden: Tachi Iai. Muso Shinden Ryu is one of the most popular koryu of iaido but it also has kumitachi kata (paired kenjutsu exercises) that run parallel to the curriculum. In fact, it has more kumitachi kata than iai kata. Many take this evidence that what we call Muso Shinden Ryu iaido today was a much bigger system consisting of not only swordsmanship but Yawara (Natsurabara Ryu) and Bojutsu (Itarabashi Ryu).
The term Entry Level is rather misleading. In a book on the related Musō Jikiden Eishin-Ryū the term Shoden is translated as Fundamental. This translation is probably more accurate in the sense that is does neither imply that the used techniques are simple nor is the subject matter for the mere benefit of beginners alone. Furthermore the source mentioned, Ogawa's Essential Kendo and others site Omori Ryokuzaimon an expert or Tatsugin in Shinkage Ryu as the originator of Shoden Kata, the first formal study of seiza, a court posture which can be traced back to Hindu yoga.
The traditional confusion in this Ryu comes from the general assumption that 'To' is the On reading for Sword when in fact this may not be true in most cases. 'To' for many kata may have been 'attack' which clarifies the original excuse for changing the names. The argument was that for example Sato and Uto were confusing. However if you substitute attack for sword then Sato means an attack from the left, Atarito is the range or area of attack, Gyakuto is reversing the attack etc. Thus Batto may in fact have a different reading than the Chinese on reading. Note there are either Hayashizaki or Mugai Ryu kata that use this same character for attack.
It should be also noted that Ryuto & Junto are the primary distinctions in kata between Muso Shinden & Eshin Jikiden, and so can be dubiously critiqued as refutation attempts.
It should also be noted that according to Kensei Kai, Nakayama did not have permission from Shimamura to pass on the true transmission of Shimomura Ha and even was required to take a vow to the same effect on order to become soke. This led to the think tank that did not reveal itself until 1933. Thus they argue at one point Muso Shinden had as much as 108 kata. The problem with this story is that if Shimomura Ha is hidden and lost how can it be rationalized that few instances exist to show real disparities between Muso Shinden and Muso Jikiden kata
Tora Issoke is often translated as the Tigers Claw or Paw, Yamashoroshi as winding down from the hillside, much like the western idea of a snowball rolling down a hill. Uroku is often used as the term for fish scales but is not exclusively so, and hence can be taken as 'scaling off' ideally.It is not clear that all of these are created by Hasegawa, only that the system was revamped by him given the popular trend toward the katana at the time.
Okuden can also be a reference to the Zen like notion of 100,000,000 transmissions, see kodansha.
The book Flashing Steel also gives the following alternative names.
Mukobari-Kasume, Tsukadome-Sunegakoi, Shisume-Four directions, Misumi-Three Corners, Mokuzume-Towaki,
Yukizure-Ikizure, Goho Giri-Five Cuts, Yuri no Naka-Shinobu, Kakurisute- Ambush, Minori, Hanashi Uchi-Sode Mae Hito Naka-The one inside or in the middle-Kabezoi
It should be mentioned that only a few dojos still practice the whole curriculum. Most organizations only practice the Iai aspect of the art. Thus the kumitachi of Muso Shinden Ryu is lost to majority practitioners.