I recently visited Nanzō-in Temple, Fukuoka Prefecture, Japan, home of a very large bronze reclining Buddha. In front of the statue are many vertical metal cylinders. My initial thought was that they are prayer wheels - and you may tell me that this is the case - but I did not see any obvious means for them to rotate. What are these cylinders?
(image from Wikimedia Commons, licensed CC BY-SA 2.0. Original at https://en.wikipedia.org/wiki/Nanzoin_temple#/media/File:Reclining_Buddha_statues_of_Nanzoin.jpg)