On a recent Tuesday in August, a group of preschoolers and elementary school pupils in Tokyo listened carefully to their cram school teacher's explanation about what would normally be a taboo subject for kids this age — sex.
"Sperm, ovum, sexual intercourse, fertilization," the children stood up and chanted in unison.
The group of 18, ages 4 to 11, were attending a class at Terakoya Annex, a cram school in Taito Ward that provides innovative education, including about sex.