59 years to November 1961 and a duck netting trip outside Tokyo that saw Princess Alexandra in a fur pillbox, Empress Nagako in a blue cuffed hat and then Crown Prince Akihito in a brown fedora, all out for Empress Michiko, who was crown princess at the time, seems to have sported a brown capulet style hat with side bow.
Thanks, Jake, for this photo suggestion!
Photo from Getty as indicated
Royal Hats 
I’m afraid the usually-glam Alexandra looks dumpy and mismatched here.
Not shown in the trip to Japan, but my favorite hat worn in Burma is Princess Alexandra’s white feather with the black spots. It’s lovely.
I’ve searched for this one but come up empty. Any links you could share?
Could this be the one?
https://reuters.screenocean.com/record/175854
If it’s not, it’s still a treasure!
Here is a one minute portion of this video, showing what happens on a duck netting trip. 1:17 to 2:20. Nagako’s blue hat show up well.
This is brilliant!
Wow! What a fantastic, historical photo! Crown Prince Akihito looks very dapper in his fedora. I quite like Empress Nagako’s blue cuffed hat. However, I am puzzled by Princess Alexandra’s choice. It’s a beautiful hat, but somehow seems out of place with her autumnal wear (fabulous skirt!).