It's O-higan...around the Spring and Autumnal Equinoxes, most Buddhist sects observe this time.
Similar to O-bon, many visit family graves and think of loved ones.
I think it is cool that every year around this time the cyclamen that we had intended to give Satoshi's grandma blooms.
If you don't know the backstory on this cyclamen, check out this post I wrote here.
Anyway, O-higan ends on the 23rd, and we are planning to visit her grave during the weekend.
Thinking of you Hikone Grandma.