Schools in Japan are bringing new meaning to the word "logbook".
The Japan Toilet Institute is asking pupils to check their stools every day and identify which of four categories of poo they resemble against descriptions produced by the institute's Li Unchi Labo (literally "Poo Lab"). Pupils then note the results in specially produced turd calendars, which have been delivered to schools.
The Asahi Shimbun newspaper reported on a recent visit by one of the institute's staff to Todoroki Elementary School in Tokyo's Setagaya ward.
Atsushi Kato, 36, arrived dressed as the "Poop Prince" and told the 80 pupils: "I've come to teach you how to do healthy poo."
He informed pupils of three rules for producing "glittering" poos: drink a glass of water in the morning, eat breakfast and exercise.
The visit was one of more than 100 arranged by the institute, which has also written a song - called the "Poo Poo Song".
At the end of the lesson, Mr Kato asked: "Have you come to like poop?" The pupils responded with a unanimous chorus of "Yes."