Later I found a poem by (Matsuo) Basho, written around 1688:
(Uncut, a pond full of lotuses is offering enough for Obon)
There is a three-day period normally in August that is Obon. Obon is a Buddhist memorial festival that dates back more than a thousand years. It is a time when families gather and the ancestors come back to their families as well. It is also a reminder of the brevity and preciousness of our lives together. There are a few rituals that are followed during these days, their exact nature differing between regions, communities and families. One of them is preparing an offering, so that the returned spirits don’t have to go hungry. In some areas this involves lotus leaves.
Here is a short overview for Obon meanings and rituals and some videos: