Hi Jason, where did you read "katate-uchi" fell out of favour by the early 1530,s?. It was my understanding that they where used by mass infantry throughout the Sengoku.
Recently ive also been wondering about their continued use in Edo times, judging by the many examples you still see in Edo koshirae.
The nakago on the sword above does look to be intended for two handed use, the nagasa seems a little short for two handed use. Many katate-uchigatana that you see are machi-okuri, a longer tsuka added. Maybe by 1547 (as the blade states), some wise folk got tired of increasing tsuka length by machi-okuri and thought what the hell, lets add a decent length grip from the start, but what do I know
Looks like the question has been answered by smarter people than me but here's a good quick summary:http://www.thesamura...ta_te_uchi.html
Bottom line, a katate-uchi essentially is an O-wakizashi (or barely past the arbitrary 2 shaku limit for a daito) 150 years or so before the definition of a wakizashi was formally enshrined in law by the Tokugawa Shogunate and decades before wearing a daisho was standard. It was intended as a "quick-draw" secondary offensive weapon for unmounted warriors but by the time of the Sengoku Jidai, trends and tactics favored the longer (2-handed ) katana over the katate-uchi. I think the so-called kazu uchi mono mass-produced blades were the "rank and file" swords of the Sengoku Jidai and they were like the OP's sword, only of much poorer quality.
This is just my own random guessing but this is also around the decades when metal plate armor showed up on the battlefield to counter matchlock guns; maybe 1-handed swords just weren't up to the task? Swords were of lessor importance on the battlefield anyway so it could have just been dictated byfashion.
Ultimately you'd have to define "katate uchi" by their short nagasa, sakisori, short nakago and having been made in that 1450-1530s time window, not to mention being mounted as one and not a wak/katana (just like how a tachi is only a tachi if you don't mount and wear it upside-down
) The concept didn't die though... instead it evolved into the shinogi zukri wakizashi as part of the daisho, so you could have the benefits of both a shorter 1-handed and longer 2-handed sword on your belt.