Hello
Not sure in that case, look at the nakago, the sori seems to be also present in the nakago.Retrempering is only the cutting part of the blade, not the whole blade, that exclude nakago.
I already saw a same kind of sword: deep sori like this one and a court koshirae with large end (sorry I forgot the name of this kind of koshirae).
I second Thomas, more photos will be appreciated.