Semi, thank you for a delightful look at Japan. And you have solved a mystery.
On my first visit to Tokyo I saw a group of teenagers with clear umbrellas. It was a sunny day, so I figured that they weren't carrying them against the rain, nor (obviously) as parasols. I decided it must be a mark of some club; carry something so utterly useless that it was a badge of honour.
Then again, I found so much of Japanese culture utterly bewildering that I didn't worry too much!
I was lucky enough to visit Kyoto one April. The Philosopher's Walk was beautiful, and doubly so with the sakura floating down the stream in dense pink islands.
I had the place to myself, apart from about a million Japanese, all taking photographs.
Hiroshima, another April, was an even more intense experience. It was a festival of pink, down to a boat cruising along the river pumping out huge floating pink bubbles, and businessmen having hanami under the trees, and drunkenly widdling into the bushes.
This April was supposed to be the Kumano Kodo pilgrimage for me, and I was so looking forward to it. I have postponed it for next year, but that's looking very iffy.
I look forward to returning. One year.