children price until which age?

i've searched expenses fee for my family to Japan
we have 3 children age 12, 9 and 7

children price is cheaper but there's no information until which age is counted as children?

also in some site counts "age 12" as adult, but "age 11 and elementary school" count as children,
in this case, my 12 yo nephew but has a letter from elemenatary school can be count as children?

thank you

In case of children, which do not visit Japanese schools, the age is what counts:

6-11: children
12+: adult

JR and most trains and buses in Japan, children price (half price) only refers to under 12 years old. I lived in Japan when I was a child of 13. I always bought child ticket until age 14 because I looked younger then (feels good now that I'm so old). No conductor ever came in the trains to ask me for ID's or birth certificate to determine my actual age.
If you are traveling on JR Pass or any pass, you cannot get away with this because it's up to the age stated on the passport.

Please understand that I'm not advocating cheating. I'm only telling you what I did when I was living in Japan age 12-15.

Some attractions, ferries, temples and shrines state elementary school. There is no law that one must be under 12. Just say "Shogakko" and they will give children price.

Chad