I'll list some facts I've found around. My translations aren't so great but I believe you will get the gist.
"Japan generally does not fluoridate its water supply, and Okinawa is
no exception. However, the traditional Japanese diet does not promote
tooth decay the way that the average American diet does, dentists
say."
"While most U.S. Forces Japan installations do not treat their
municipal water, Misawa Air Base fluoridates water on its main base
and north area with sodium fluoride, at a cost of about $6,500 per
year, according to Maj. Monte Harner of the 35th Civil Engineer
Squadron."
http://www.stripes.com/news/water-on-okinawa-bases-no-longer-fluoridated-1.35435
The maximum level of fluoride by the Water quality standards is 0.8ppm.
https://www.jda.or.jp/park/prevent/index05_13.html
"Views on fluoride applications for dental caries prevention program
in 1982 Japan oral hygiene Society Fluorine Research Group Recommend
fluoride application it is recommended the application of fluoride for
dental health
- Fluorine is a need for dental health, after the formation phase and eruption of teeth, is more effective throughout life.
- Application of fluoride, which is carried out in the dental health management is safe.
- For the children of caries prevention, programs of public health fluoride application is effective.
- Application of fluoride has been recommended internationally widely."
http://www.niph.go.jp/soshiki/koku/oralhealth/ffrg/m/kenkai1.html
Ministry of Health and Welfare Health Policy Bureau Dental Health Division and living Health Water Environment Department
consensus document of the Ministry of Health and Welfare Dental Health Division (December 6, 2000) said:
"1)For fluoride application, including the addition of fluoride to tap
water, you are recognized as a challenge while watching the progress
of welfare science research, it will consider.
2)From local government, if there is a request of technical assistance
for the addition of fluoride in the water quality standards (0.8㎎ / 1L
below), water suppliers, water users, on the assumption the
understanding such as local Dental Association, and the Health Science
I want to continue depending as part of the dental health
administration such as by utilizing the results of research."
http://www.niph.go.jp/soshiki/koku/oralhealth/ffrg/m/kenkai2.html
"In Japan, water fluoridation have been made as a test study in Kyoto
Yamashina district from 1952 to 1965. Any Other in Okinawa Prefecture
(1957-73 years) and Mie Prefecture Asahi-machi (1967-72 years) may
have been carried out. Both unfortunately now has been discontinued,
but it is where the resume is desired."
http://www.e-healthnet.mhlw.go.jp/information/teeth/h-02-010.html
But looks like instead of water fluoridation, Japan promotes fluoridated mouthwash.
"To "health promotion 8020 promotion regulations of Hokkaido
tooth-mouth", which came into effect in June 2009, the promotion of
fluoride mouthwash in elementary and junior high schools as an
effective dental health measures have been incorporated. For dental
caries prevention of students of the main road in Hokkaido Board of
Education, and we are actively promoting the fluoride mouthwash in
school."
http://www.dokyoi.pref.hokkaido.lg.jp/hk/ktk/hukkabutu.htm
http://www.fukushihoken.metro.tokyo.jp/iryo/iryo_hoken/shikahoken/pamphlet/susumeyoufukkabutsuouyou.html