Ōmori developed a series of eleven Iai techniques, combined with the formal Seiza seating position of the Ogasawara School of etiquette. Eishin would later re-admit Ōmori to the Muso Ryū School for this innovation. Keep in mind this important fact as we go forward – the Ōmori techniques were a training innovation developed from Yagyu Shinkage Ryū, and Eishin Ryū Tatehiza no Bu, both late Muromachi period schools of swordsmanship.
To Summarise then, is Seiza a Real Samurai Fighting Position? Yes, in a sense, but like the koryu themselves a simple sitting position such as seiza is layered with depth and meaning, as is the school from which it takes it name. With regards to the objections to seiza and the consistent admonishment by those outside of the Musō Jikiden Eishin-ryū that seiza shows that the ryū is not a koryu or reflective of feudal period Japanese swordsmanship I would ask them to reflect on the following points:
1. The Samurai wore their long swords in seiza in certain situations like Joiuchi, bodyguarding and of course, when practicing the Ōmori-ryū
2. The posture of seiza is an Edo period modification of accepted Muromachi period posture such as iidori and this is in keeping with the high level of jūjutsu within the curriculum.
3. The seiza posture taken during Ōmori-ryū Seiza no bu teaches important principles and techniques applicable in formal Edo period setting where a wakizashi, tanto or yoroidoshi would have been worn.
4. Within the Ōmori is an introduction to the techniques and principles of Muromachi period, feudal Japanese combat, from which the Ōmori have been inspired.
5. The seiza posture affords useful teaching points and assists with the correct physiological patterns required for the core teachings of the style.
6. The posture of seiza is not reflective of the Musō Jikiden Eishin-ryū, given that it comprises between 6.7% – 11% of the total curriculum.
7. Koryu Bujutsu are not solely concerned with combative function. They are layered with spiritual, religious and philosophical teachings and the seiza posture imparts specific spiritual teachings to the students of the ryū separate to any concerns one may have about „realistic combat“.