It really just checks all the boxes for me and I had been looking at it for a while but was just searching for something cheaper. I had originally been pretty close to buying this a while back https://www.aoijapan.com/katanamumeiunsigned-attributed-to-den-nakajima-rai-中島来the-17th-juyo-tokenmenukinbthk-hozon-tosogu/
I stopped however once I found out it has a big patch of umegane on the ji (not in the description but look on the image and you can see it, confirmed by Aoi Art). But I really enjoyed the sugata combined with the double hi, not to mention the Rai workmanship of this one. That lead me to look around for other swords with a similar style and I am a huge fan of Bizen (my favorite tradition) history, workmanship and style in general.
I had kind of written this one off a bit because of the price, but it really has it all for me. Warring period, Bizen, uroi, utsuri, ubu, long signature, dated, healthy. I find the warring period Bizen swords especially interesting for a few reasons. You do see the Sue-Bizen description thrown around as undesirable by many, but this is mainly because of the overall average of work during this period and the writings about such. It is true, however multiple things can be true at once, and a key thing to remember, as evidenced by the rare masterpieces crafted during this time, is that the smiths did not "forget" how to produce swords with uroi, utsuri, they just weren't doing it for the most part. I am guessing due to time and material constraints combined with needs of the times and other things that have been mentioned in this forum. These were still essentially unbroken traditions and lineages of smiths before the destruction of Osafune. So when I see a Bizen masterpiece come out of that historically important and bloody time, it has always peaked my interest.
I have a sword signed only Bishu Osafune Sukesada, but it is one of my favorite pieces in the collection and is overall one of the most interesting and beautiful Bizen pieces I've held, largely due to the (imo) insanely beautiful sashikomi polish on it. It is like the sun behind clouds.