I have a dated, color photo book (coffee table size) on the Pacific War which offers photos of a significant collection of showa period swords.
The photo attributes the swords to the "MacArthur Collection." I had heard some stories in old reference works that the General had a fair number of Japanese swords (not shocking to me). I finally made a trip back to the museum this past Fall ... but was disappointed in the displays. There were only 4 swords displayed in the entire museum (which, by the way, is quite large). Three of the swords are attributed to famous generals (Togo and Yamashita) You will notice in the photos it says that the sword is "reported to have" belonged to Yamashita. I have my doubts (... just an opinion). I apologize for the quality of photos - hard to take good shots with my phone and the glass case.