Hello:
I am getting into this rather late and am usually very reluctant to criticize anything for sale, but there are limits.
My Tsuruta or his staff describes it as "Gunto", so perhaps an indication of something there or a red flag, however his oshigata clearly shows a well defined hamon and that wouldn't fit with oil tempered if it is true to what is seen. I think there might be another stamp that had been on it to the left of Brian's indication and at the same level.
The biggest caution must be taken from the different yasuremi on the ura if carried as an uchigata-katana as it seems, curiously, to have been intended for. It is so deep and so different from the other side. For those just starting collecting I cannot stress strongly enough the importance of the nakago, not just the mei, but all of the proportions and the yasuremi must fit the period of manufacture, and correct yasuremi tends to vary little in any characteristic side to side. What might have been there? A shocking proportion of the value of any blade, ubu or suriage, is found in the nakago!
I would not condemn any blade entirely without seeing it in hand, but I am very suspicious.
Arnold F.