For those wondering why they left a bottle of water for the victims of disaster, it's part of a Japanese ritual for the dead. It's called 末期の水 or last moment's water. This is where water is offered to the dying person moments before, or immediately after passing - by moistening the lips of the soon-to-be-deceased. In some cases, people also leave a cup or bowl of water on the grave. The idea is to wish or provide the dead a comfortable travel to the afterlife. In legends, they say that in the Buddha's dying moment he complained that he was thirsty, and a follower gave him water, which made the Buddha be relaxed and be sent off in peace.