The reason I write and post things on blogs such as this is to try to end the confusion that often surrounds ninjutsu. Past things I have put up on the internet about the Koga ryu, the Godai and such help folks to correct mistaken impressions, and there are a lot of them in the art of ninjutsu.
One of the most pervasive ones is the idea that the ninja used a straight bladed sword because they could not afford to make ones like those used by the samurai. This mistaken impression is one of the most common ones and seems unwilling to die.
As far as some of us can tell the idea came about from the writings of a Westerner, Stephen Hayes, and then spread around the world due to the volume of his writings and the influence they had. First they showed up in the West, then they showed up in Hong Kong movies and now they even can be found in Japan!
If the last surprises you, it should be noted that there is no mention of the ninja using straight bladed swords in a Japanese source prior to Hayes writing that they did.
All the evidence so far points to this being a mistake by Hayes due to a misunderstanding of the subject matter on his part. According to Japanese teachers who were there when he was actually training in Japan, he could not get to many classes, his Japanese ability is still very poor and he never advanced far enough to learn things like sword. Viewed in this light, mistakes are to be expected. Many people think that the ninja used straight swords because the story is also included in the book "Ninjutsu, History and Tradition" accredited to Masaaki Hatsumi. However, that book is not a straight translation, but a collection of things taken from some stuff Hatsumi had printed in Japanese with some "explanation" added in by Hayes.
It is important to note that there are no Japanese sources by Hatsumi where he says that the ninja used straight blades. In addition, he and other Japanese have denied that they use them when asked. There was even a humorous incident when Fumio Manaka first laid eyes on a practice wooden sword with a straight blade and asked what they heck it was and why people were using them in ninjutsu training. In sources in English where Hatsumi had a great amount of control, there is no mention of the ninja using straight bladed swords. The only references we can find in any language are in English. One of them is the previously mentioned book, the other seems to be something added by an editor of the now defunct Ninja Magazine and does not originate with Hatsumi.
To those not familiar with the publishing world, editors do add their own copy to articles and such. Sometimes it is to make clearer what the writer is saying. Sometimes it is to add in some details they think were overlooked. And sometimes they even do it to make a short article a bit longer. The passage attributed to Hatsumi in the Ninja Magazine article is so close to the terms first written by Hayes that most objective folks have concluded that it was the source of what the editors added.
It is not just the similarity in writing style, though that is fairly clear if you are familiar with translations, that convince folks that the passage was added by the editors. The fact that Hatsumi has denied that the ninja used straight swords when asked, all his Japanese members have confirmed that he never said anything of the sort and the lack of a single source in Japanese by Hatsumi also is overwhelming evidence that Hatsumi never said that the ninja used straight swords.
And it is safe to say that the ninja did not use straight swords.
Logically, it makes no sense. When crafting a blade, it is not easier to make a straight blade compared with a curved one. The ninja also would not want to stand out with a different blade if they could help it. If the ninja were using a blade different from the norm, it would cause notice and someone would make mention of it in an historical source. So far, no one has been able to find such a source and give its name.
Indeed, after writing for years that the ninja used a straight blade and even licensing his name to a series of weapons including straight bladed training swords with Taipei, Hayes reversed himself in one of his books by Ohara Publications and claimed that the idea that the ninja used a straight sword was a cultural myth. He claimed that the common people thought that the ninja used a straight blade due to their association with Fudo Myo- ou and not because they ninja actually used them.
This last part is a little strange since you would assume that if Japanese people mistakenly thought that the ninja used straight blades, we would be able to find some sort of reference to the ninja using them. If they did use them, then there would be historical references that could be named where people commented on it. If it were a common mistake, then you would assume that historians and writers would take the time to correct the mistake.
However, there is NOTHING in Japanese we have been able to find before Hayes started writing about the straight bladed ninja sword. Hatsumi in his "Ninpo Zukan" book only notes that the sword was shorter. Authors such as Yumio Nawa never mention anything about the ninja using a straight sword either as if it were fact, or a mistake they need to correct their reader's impression of. The lack of any source saying anything about the ninja using a cruder, straight blade in Japanese by historians and writers should be looked at in the same light as the lack of reference to American Indians using machine guns. There is no reference in any way because there was nothing to support the idea.
Since the ninja made a large splash in the West, there is now some places that cater to this image of the straight bladed sword. While serious publications in Japanese still do not say that the ninja used straight swords, the ninja museum in Iga Ueno in an attempt to attract foreign tourists have added a modern made straight bladed ninja sword made in Taiwan. The museum is really more of a tourist trap than a serious museum and they have no actual historical examples of the ninja sword and so they have to use one made in the last few years instead.
Why did Hayes think that the ninja used straight swords? We may never know unless he chooses to tell us. Hayes is also famous for the story that the ninja were an oppressed minority, hunted and hated because of their mystic powers. This mistaken view of history is the background for the need for an easily made sword. The reality is far different.
Certainly we can say the following,
-There is no mention of the ninja using a crudely made, straight sword in anything written by Hatsumi in Japanese.
-He and several of the senior Japanese teachers in the Bujinkan have denied that the ninja used such weapons when asked.
-No Japanese historian seems to have made mention of the ninja using a straight sword.
-There are no historical sources that have been named that talk about the ninja using a crude, straight sword.
-The ninja were not an oppressed minority and they did have access to regular swords.
-The idea that a straight sword is easier to make than a curved one is false.
So I hope that people reading this will know that those that portray themselves as previously secret ninja traditions come to light in the 20th century and use their traditional straight sword are in fact using a weapon that did not exist prior to 1980. So the secret traditional version of ninjutsu they claim to teach is probably no older than the cars they drive.