I'm very new to Nihonto but have been trying to learn more by purchasing books, reading up on the art of the Japanese sword, its history, forms of creation, and preservation. In starting a collection (and buying my first blade), I've narrowed my focus to the Muromachi period, in particular, the early half of this era before the mass production of swords for use in the waring states period initiated by the Onin War in 1467. I've also focused in on purchasing a longer wakizashi or shorter katana given the highly constrained space in my current living environment (+ easier to keep in a limited-dimension, humidity regulated display case).
I've identified two blades which have all of the characteristics I've been looking for:
1. Morimitsu wakizashi: (1,800,000 JPY) https://ginzaseikodo.com/en/product/swords/morimitsu/
2. Yasumitsu Wakizashi: https://www.aoijapan.com/wakizashi-yasumitsu/ (800,000 JPY)
Both blades come with a koshirae, were made by oei bizen smiths (Morimitsu and Yasumitsu were supposedly even brothers), have NBTHK Tokubetsu Hozon tokens, were signed, and have similar dimensions and looks. However, the one by Morimitsu costs 1,800,000 JPY while the one by Yasumitsu is 800,000 JPY. The hamon looks relatively similar to my untrained and inexperienced eye, although perhaps the hamon in the boshi of the Morimitsu is a little more vivid. The biggest difference difference to me, a highly inexperienced perspective, is the presence of a date on the former and the lack of a date on the latter.
Is the presence of a date the reason the Morimitsu blade costs 1,000,000 JPY more than the one by Yasumitsu? What am I missing?