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Japan 50Hz or 60Hz? The east–west split, prefecture by prefecture

Eastern Japan runs on 50Hz and western Japan on 60Hz. The line runs around the Fuji River in Shizuoka and Itoigawa in Niigata (Kansai Electric Power). The voltage is 100V on both sides, and a label that says 50/60Hz works everywhere.

Updated

14prefectures on 50Hz
29prefectures on 60Hz
4prefectures with both

Which half of Japan is which

The line runs around the Fuji River in Shizuoka and Itoigawa in Niigata. 14 prefectures are on 50Hz, 29 on 60Hz and 4 have both.

Map of Japan's 47 prefectures: 14 on 50Hz in the east, 29 on 60Hz in the west, and Gunma, Niigata, Nagano and Shizuoka with both.

Figure by japan-japan.com from the wheeling service terms of Japan's 10 general transmission and distribution companies (effective 1 October 2026).

Kansai Electric Power (English page)The electric frequency is different on either side of the Fujigawa River in Shizuoka Prefecture and Itoigawa City in Niigata Prefecture, with 50Hz in the east and 60Hz in the west.Kansai Electric Power
All 47 prefectures by frequency
Japan's prefectures by mains frequency (tariffs of the 10 companies, October 2026)
FrequencyPrefecturesWhich
50Hz14Hokkaido, Aomori, Iwate, Miyagi, Akita, Yamagata, Fukushima, Ibaraki, Tochigi, Saitama, Chiba, Tokyo, Kanagawa, Yamanashi
60Hz29Toyama, Ishikawa, Fukui, Gifu, Aichi, Mie, Shiga, Kyoto, Osaka, Hyogo, Nara, Wakayama, Tottori, Shimane, Okayama, Hiroshima, Yamaguchi, Tokushima, Kagawa, Ehime, Kochi, Fukuoka, Saga, Nagasaki, Kumamoto, Oita, Miyazaki, Kagoshima, Okinawa
Both4Gunma, Niigata, Nagano, Shizuoka

The 10 power grid companies

Each company's wheeling service terms state one standard frequency. Three of them keep a part of a prefecture on the other frequency.

Standard frequency and supply area of Japan's 10 general transmission and distribution companies (terms effective 1 October 2026)
CompanyFrequencyArea
Hokkaido Electric Power Network50Hz TermsHokkaido
Tohoku Electric Power Network50Hz TermsAomori, Iwate, Akita, Miyagi, Yamagata, Fukushima, NiigataParts of Sado, Myoko and Itoigawa in Niigata that were on 60Hz when the terms took effect stay on 60Hz for now.
TEPCO Power Grid50Hz TermsTochigi, Gunma, Ibaraki, Saitama, Chiba, Tokyo, Kanagawa, Yamanashi, Shizuoka (east of the Fuji River)Part of Gunma that was on 60Hz when the terms took effect stays on 60Hz for now.
Chubu Electric Power Grid60Hz TermsAichi, Gifu (except some areas), Mie (except some areas), Shizuoka (west of the Fuji River), NaganoPart of Nagano that was on 50Hz when the terms took effect stays on 50Hz for now.
Hokuriku Electric Power Transmission & Distribution60Hz TermsToyama, Ishikawa, Fukui (except some areas), Gifu (some areas)
Kansai Transmission and Distribution60Hz TermsShiga, Kyoto, Osaka, Nara, Wakayama, Hyogo (except some areas), Fukui (some areas), Gifu (some areas), Mie (some areas)
Chugoku Electric Power Transmission & Distribution60Hz TermsTottori, Shimane, Okayama, Hiroshima, Yamaguchi, Hyogo (some areas), Kagawa (some areas), Ehime (some areas)
Shikoku Electric Power Transmission & Distribution60Hz TermsTokushima, Kochi, Kagawa (except some areas), Ehime (except some areas)
Kyushu Electric Power Transmission and Distribution60Hz TermsFukuoka, Saga, Nagasaki, Oita, Kumamoto, Miyazaki, Kagoshima
Okinawa Electric Power Company60Hz TermsOkinawa
Hokkaido Electric Power Network: wheeling service terms (October 2026)周波数は，標準周波数 50 ヘルツといたします。Hokkaido Electric Power Network

In English: The frequency is a standard frequency of 50 hertz.

The 4 prefectures with both

Gunma, Niigata, Nagano and Shizuoka have areas on each frequency. The terms name the cities only for Niigata.

Niigata

Tohoku Electric Power Network: wheeling service terms (October 2026)この約款実施の際現に次の区域内で標準周波数60ヘルツで電気を供給している区域については，当分の間，標準周波数60ヘルツで供給いたします。新潟県佐渡市，妙高市および糸魚川市Tohoku Electric Power Network

In English: Areas already supplied at a standard 60 hertz when these terms took effect will be supplied at 60 hertz for the time being: Sado, Myoko and Itoigawa in Niigata.

Gunma

TEPCO Power Grid: wheeling service terms (October 2026)この約款実施の際現に次の区域内で標準周波数60ヘルツで電気を供給している区域については，当分の間，標準周波数60ヘルツで供給いたします。群馬県の一部TEPCO Power Grid

In English: Areas already supplied at a standard 60 hertz when these terms took effect will be supplied at 60 hertz for the time being: part of Gunma.

Nagano

Chubu Electric Power Grid: wheeling service terms (October 2026)この約款実施の際現に次の区域内で標準周波数50ヘルツで電気を供給している区域については，当分の間，標準周波数50ヘルツで供給いたします。長野県の一部Chubu Electric Power Grid

In English: Areas already supplied at a standard 50 hertz when these terms took effect will be supplied at 50 hertz for the time being: part of Nagano.

Districts that Chubu Electric Power Miraiz lists

Chubu Electric Power Miraiz愛知県・岐阜県（一部を除きます。）・三重県（一部を除きます。）・静岡県（富士川以西）・長野県は、原則60ヘルツにて供給しておりますが、下表の地区においては50ヘルツにて供給している場合があります。Chubu Electric Power Miraiz

In English: Aichi, Gifu (except some areas), Mie (except some areas), Shizuoka (west of the Fuji River) and Nagano are supplied at 60 hertz in principle, but the districts below may be supplied at 50 hertz.

Chubu Electric Power Miraiz（1&2）下水内郡栄村、（3）下高井郡野沢温泉村、（4）飯山市、（5）小諸市、（6）佐久市、（7）松本市、（8）安曇野市穂高町、（9）大町市平区、（10）北安曇郡小谷村Chubu Electric Power Miraiz

In English: Sakae (Shimominochi District), Nozawa Onsen (Shimotakai District), Iiyama, Komoro, Saku, Matsumoto, Hotaka in Azumino, Taira in Omachi, Otari (Kitaazumi District)

Shizuoka

East of the Fuji River is TEPCO Power Grid's area on 50Hz. West of it is Chubu Electric Power Grid's area on 60Hz.

Where east and west connect

Power sent between the two halves has to be converted to the other frequency. The converters handle 2,100MW today, rising to 3,000MW from December 2028 (OCCTO, March 2026).

Frequency converter stations between 50Hz and 60Hz Japan (Agency for Natural Resources and Energy, Chubu Electric Power Grid, OCCTO)
StationWhereCapacityStatus
Shin-Shinano Frequency Converter StationNagano600MWIn use
Sakuma Frequency Converter StationShizuoka300MWIn use
Higashi-Shimizu Frequency Converter StationShizuoka300MWIn use
Hida-Shinano Frequency ConverterTakayama in Gifu and Asahi in Nagano, joined by a DC line900MWIn use since 31 March 2021
Shin-Sakuma Frequency Converter Station (new)Shizuoka, near Sakuma300MWnewPlanned, December 2028
Higashi-Shimizu Substation (more converters)Shizuoka600MWadded, 900MW in totalPlanned, December 2028

Converter capacity

2,100MWin use now
3,000MWafter the expansion
December 2028planned start of use

Source: OCCTO, FY2026 supply plan summary (March 2026)

Agency for Natural Resources and Energy (teaching material)東西で電力を融通する場合、同じ周波数に変換しなければならない。Agency for Natural Resources and Energy

In English: To exchange power between east and west, it has to be converted to the same frequency.

OCCTO (Organization for Cross-regional Coordination of Transmission Operators), March 2026○東京中部間連系設備等概要：2,100MW→3,000MW（使用開始：2028年12月）FC増設･新佐久間周波数変換所:300MW･東清水変電所:300MW→900MWOCCTO

In English: Tokyo–Chubu interconnection: 2,100MW to 3,000MW, in use from December 2028. Added converters: Shin-Sakuma Frequency Converter Station 300MW; Higashi-Shimizu Substation 300MW to 900MW.

Why Japan has two frequencies

German generators in Tokyo and American generators in Osaka, in the Meiji era.

Agency for Natural Resources and Energy (teaching material)東西地域の周波数を50Hz、60Hzに分化させるきっかけは、明治時代に東京電灯浅草発電所がドイツ製50Hz発電機を、大阪電灯幸町発電所がアメリカ製60Hz発電機を導入したことである。大正時代初頭から第2次世界大戦直後までに4回の周波数統一の動きがあったが、いずれも莫大なコストと時間がかかり、設備の改造過程で供給力不足を招くことから実現されず、現在も2つの周波数が使用されている。Agency for Natural Resources and Energy

In English: The split into 50Hz and 60Hz began in the Meiji era, when Tokyo Dento's Asakusa power station brought in German-made 50Hz generators and Osaka Dento's Saiwaicho power station brought in American-made 60Hz generators. There were four moves to unify the frequency between the early Taisho era and just after the Second World War. None went ahead because of the huge cost and time and the supply shortages the conversion would cause, so two frequencies are still used today.

What it means for your devices

Read the frequency on the label. 50/60Hz works on both sides. Hokkaido Electric Power Network and Chubu Electric Power warn about devices made for one frequency only.

Label says 50/60Hz
Works in eastern Japan (50Hz) and western Japan (60Hz)
Label says 50Hz or 60Hz only
Hokkaido Electric Power Network and Chubu Electric Power say it can break, lose performance or cause a fire on the other frequency
Voltage
100V on both sides (JNTO)
Hokkaido Electric Power Network50Hzまたは60Hz専用の機器を、違う周波数で使用すると、故障したり、最悪の場合事故につながることもあるので、注意しましょう。Hokkaido Electric Power Network

In English: Using a device made only for 50Hz or only for 60Hz on the other frequency can break it, or in the worst case lead to an accident.

Chubu Electric Powerヘルツの違いを確認せず誤って使用すると、器具を傷めたり性能を低下させるばかりか、火災の原因にもなりかねません。Chubu Electric Power

In English: Using an appliance by mistake without checking the hertz can damage it or lower its performance, and can even cause a fire.

How to read INPUT on a charger: 100-240V includes Japan's 100V, 220-240V does not. 50/60Hz works in east and west Japan.

Figure by japan-japan.com. Japan's 100V and 50/60Hz from JNTO.

Frequently asked questions

Is Tokyo 50Hz or 60Hz?

50Hz. Tokyo is in TEPCO Power Grid's area, which supplies 50Hz under its terms.

Is Osaka 50Hz or 60Hz?

60Hz. JNTO lists Nagoya, Kyoto and Osaka in western Japan on 60Hz.

Do I need to worry about 50Hz and 60Hz in Japan?

Not with a device labelled 50/60Hz, which works on both sides. Hokkaido Electric Power Network says devices for only one frequency can break on the other.

Related items

Official page: Kansai Electric Power

Sources for this page

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Compiled by Japan Japan !! · Updated October 3, 2026