Yes, I had read that also. I have seen various wakizashi mounted in Gunto koshirae (the 2010 post in the NMB archives show several). I saw a naginata naoshi in SF maybe 10-12 years ago that was mounted in a Gunto Koshirae which had also been cut down to fit the blade perfectly. It was outstanding. So we know wakizashi in Gunto mounts while not seen on a daily basis, do exist.
The point or focus of my question however is much more specific in looking only for "Mantetsu" wakizashi. I have scoured every book, the internet, contacted various collectors, etc., etc., to no avail.
Steve's quote that you pasted sums up a reasonable criteria perfectly and reveals that there is no rule regarding length of blades in general, being made to fit. So, it seems reasonable that there would be others, and in fact I can not make myself believe there are not others.
Yet, I can find no reference of any other, much less another extant Mantetsu wakizashi.
If you or anyone finds one or info, please post it.
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