Before bidding Senjuin, I was the one incorrectly went with Jitsua. I have seen/handled a couple of pieces which had a jihada that seemed consistent with the work in Jean's sword. Jitsua attributes include a suguha-based hamon with an indistinct nioi-guchi, blackish jigane with strong, flowing itame and a deki that appears rustic (outside the mainline). I steered away from Norishige and Ko-Uda based on Tanobe's comments in the sayagaki. A suguha hamon lacking in brightness is not a trait of Norishige. A date of 1301 would I believe also be too early for a smith from the Ko-Uda school. There additionally did not appear to be a mitsumune, though I am not certain that is correct based on the angle we can see in the photos.
As far as why Senjuin, there are two mainline Yamato schools which seem similar to or at times mistaken for early Soshu: Taema and Senjuin. The fact that I am very familiar with a Juyo Senjuin wakizashi that Kanzan previously attributed to Norishige is probably why I bid Senjuin after Jean gave the hint pointing to the Yamato mainline. A very challenging and fun exercise. Thank you again Jean.
Regards,
Ray