In class I will often talk about the difference between how samurai and ninja moved when walking and running because it is directly connected to the movement of our martial art. I found this video clip today from a movie. It shows the struggle of the old warriors trying to adapt to the modern age. Their way of walking was more relaxed than the modern military marching, and the way of running was slower, but specifically designed to work better for carrying swords. When you have swords in your Obi, you don't want to run or even walk with your arms and feet in opposite, contralateral, motion. This was something that the early Dutch sailors noticed about the Japanese samurai, that they walked very differently from everyone else they were used to seeing. This is one reason for the unilateral movement of the Bujinkan, it is part of a very old history of warrior ship. It is also one thing that feels very foreign to most new students to the Bujinkan Dojo, especially if they've trained in a Gendai Budo (modern martial way) arts like Karate, Aikido, Taekwondo, Judo, or any number of other new martial arts. Sometime understanding the "why" helps improve the application. Yes, modern running is faster, you'll never see Olympic runners using a samurai run, unless a new event is created where the runners have to wear Daisho (great and short swords) in a belt at their hip. Then they will naturally adapt to this older form of running to allow for proper retention of swords while running. And this is why in training Ninjutsu we move in unilateral ways. Gambatte!
Shane Sensei is a licensed Shidoshi in the Bujinkan and member of the Shidoshi-Kai. He has trained in the Bujinkan since 1998 and regularly travels to Japan for training.