mathematics

Telephone numbers in Japan

Telephone numbers in Japan is a mathematics topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Telephone numbers in Japan rather than just read about it. In short: Telephone numbers in Japan consist of an area code, an exchange number, and a subscriber number. Dialing prefixes 001, 00xx, 002xx, 0091xx Carrier selection prefix 184 Prefix to withhold caller ID 186 Prefix to provide caller ID Types of numbers 1xx Special numbers 001 and 00xx Carrier selection codes 0x 2-digit geographic area codes 0xx 3-digit geographic area codes 0xxx 4-digit geographic area codes 0xxxx 5-digit…

Key takeaways

Telephone numbers in Japan belongs to mathematics; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Telephone numbers in Japan to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Telephone numbers in Japan from memory before moving on to harder problems.

Reference excerpt

Telephone numbers in Japan consist of an area code, an exchange number, and a subscriber number.

Dialing prefixes 001, 00xx, 002xx, 0091xx Carrier selection prefix 184 Prefix to withhold caller ID 186 Prefix to provide caller ID

Types of numbers 1xx Special numbers 001 and 00xx Carrier selection codes 0x 2-digit geographic area codes 0xx 3-digit geographic area codes 0xxx 4-digit geographic area codes 0xxxx 5-digit geographic area codes 0x0 3-digit non-Geographic area codes (excluding 010) 0xx0 4-digit non-Geographic area codes (01x0, 0570, 0800, 0910, 0990)

Length of numbers Special numbers are three digits long Geographic numbers are ten digits long 0X0 Non-geographic numbers are 10 or 11 digits long 0XX0 Non-geographic numbers are 10 digits long

Three-digit numbers (special numbers)

Emergency services

110 Police (112 and 911 redirect to 110 on mobile phones) 118 Maritime emergencies 119 Ambulance, Fire brigade 171 Earthquake assistance

Operator services

100 NTT operator 106 Operator assisted collect call service 108 Automated collect call service 113 NTT technical faults hotline 116 NTT customer service and general enquiries

Directory services 104 NTT national directory enquiries 0057 KDDI international directory enquiries

Special services 114 Automated number-busy check 115 Telegram service 117 Speaking clock 136 Information on last incoming call 177 Weather forecast

Long-distance carrier selection (Myline)

001 KDDI (international) 0032 IPS Inc. 0033 NTT Communications 0034 NTT Communications (international toll free) 0036 NTT East 0037 Fusion Communications 0039 NTT West 0041 SoftBank Telecom (international / former Japan Telecom) 0053 KDDI (Resold) 0056 KDDI (international) 0061 SoftBank Telecom (international / former Cable and Wireless IDC) 0066 SoftBank Telecom (international / former Cable and Wireless IDC) 0070 KDDI Toll Free 0071 Verizon Japan 0077 KDDI (national) 0080 T-Systems 0081 Fusion Communications (former TTNet) 0088 SoftBank Telecom (national / former Japan Telecom) 0089 T-Systems 0091 Brastel

Ten-digit numbers

Non-geographic area codes 0120 NTT Freedial, toll free services 0130 Automated information services 0140 Disaster relief wireless communications 0160 Disaster relief satellite communications 0170 NTT Dengon Dial, chat line services 0180 NTT Telegong, TV/Radio show feedback dial-in 0180 NTT Teledome, automated information services 0190 NTT Angel Line, automated directory services via PC/modem 0190 NTT Annai Jozu, automated directory services via telephone 0570 Navi Dial 0800 Other toll free services 020 Paging services (PDC) and data services (UMTS) 030 Mobile telephony services (legacy systems, PDC, J-CDMA, UMTS) - currently not used 040 Mobile telephony services (legacy systems, PDC, J-CDMA, UMTS) - currently not used 050 IP telephony service (via internet service providers) 060 Universal personal number services 070 Mobile telephony and data services (PDC, J-CDMA, UMTS) 080 Mobile telephony and data services (PDC, J-CDMA, UMTS) 090 Mobile telephony and data services (PDC, J-CDMA, UMTS) 0910 Private circuit access, local rate services 0990 NTT DialQ2, premium rate services

Decommissioned area codes 0150 formerly used for maritime wireless communications 0450 formerly used for maritime wireless communications 0750 formerly used for maritime wireless communications

Area codes (市外局番 "shigai-kyokuban") of selected major cities 11 Sapporo 138 Hakodate 166 Asahikawa 17-7　or 172 Aomori 18-8 Akita 19-6 Morioka 22 Sendai 23-6 Yamagata 24-5 Fukushima 24-6 Iwaki 24-9 Kōriyama 25 Niigata 26 Nagano 27-2 Maebashi 27-3 Takasaki 28-6 Utsunomiya 3 Tokyo (23 Special wards), Komae 4-29 Tokorozawa 4-70 Kamogawa 4-71 Kashiwa 42-6 Hachiōji 42-7 Machida, Sagamihara 43 　Chiba 44 Kawasaki 45 Yokohama 466 Fujisawa 46-8 Yokosuka 47-3 Ichikawa, Matsudo 47-4 (473 for west part of the city) Funabashi 48-2 Kawaguchi 48-6 or 48-7 or 48-8 Saitama 48-9　Soka, Koshigaya 49 Kawagoe 52 Nagoya 53 Hamamatsu 53-2 Toyohashi 54 Shizuoka 55 Kofu 564 Okazaki 565 Toyota 568 Kasugai 569 Handa 58 Gifu 586 Ichinomiya 592 Tsu, Yokkaichi 6 Osaka, Higashiōsaka, Suita, Toyonaka, Amagasaki 72-2 Sakai 726 Takatsuki 72-8 Hirakata 73 Wakayama 742 or 743 Nara 75 Kyoto 76-2 Kanazawa 76-4 Toyama 768 Suzu 77-5 Ōtsu 776 Fukui 78 Kobe 790 Kasai 792 or 793 Himeji 794 Kakogawa 797 or 798 Nishinomiya, Takarazuka 82 Hiroshima 832 or 834 Shimonoseki 839 Yamaguchi 84 Fukuyama 852 Matsue 857 Tottori 862 or 869 Okayama 864 or 865 Kurashiki 87 Takamatsu 88-6 Tokushima 88-8 Kochi 89 Matsuyama 92 Fukuoka 93 Kitakyushu 942 Kurume 95-8 Nagasaki 952 Saga 956 Sasebo 96 Kumamoto 97 Ōita 98-8 or 98-9 Naha 981 or 98-5 Miyazaki 99 Kagoshima

Geographic numbers are nine digits long, including the area code, but not including the leading zero. Consequently, densely populated areas have shorter area codes, while less populated areas have longer area codes. For example:

6 xxxx xxxx (Osaka) 75 xxx xxxx (Kyoto) 742 xx xxxx (Nara) 4992 x xxxx (Niijima island, Tokyo pref.) 82486 xxxx (Takano, Hiroshima pref.) Area codes increase from north to south; Sapporo in Hokkaidō (the northernmost prefecture) has 11, and Setouchi's 99-73 is far to the south in Kagoshima. When the telephone system was devised, Okinawa was still under U.S. occupation, so when it was returned to Japan in 1972, its telephone numbers were squeezed between Miyazaki (98x) and Kagoshima (99x) and begin with 988, 989, and 980. During the 1990s, when plans were being drawn up to amalgamate mid-sized cities and towns into larger municipalities, telephone numbering systems were merged in advance. For example, in Nara Prefecture:

7442 x xxxx Kashihara 7444 x xxxx Sakurai 74452 xxxx Takatori 74454 xxxx Asuka etc. became:

744 2x xxxx Kashihara 744 4x xxxx Sakurai 744 52 xxxx Takatori 744 54 xxxx Asuka etc. Many of these towns have in fact refused to merge, leaving callers with more digits to dial when making local calls. This is partially balanced by not having to dial an area code for the neighboring city.

Area code as local brand naming

… excerpt ends here. Continue reading the full article.

Worked examples

Example 1 — a first encounter with Telephone numbers in Japan

Start with the simplest possible case. Write down what Telephone numbers in Japan claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In mathematics, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Telephone numbers in Japan before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Telephone numbers in Japan ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Telephone numbers in Japan

In research: Telephone numbers in Japan appears in mathematics research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Telephone numbers in Japan in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Telephone numbers in Japan is common in secondary-school and first-year university syllabi. It links to neighbouring topics Telephone numbers by country, Telephone numbers in Japan, so understanding it makes those chapters shorter.
In everyday life: Look for Telephone numbers in Japan outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Telephone numbers in Japan in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Telephone numbers in Japan means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Telephone numbers in Japan out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Telephone numbers in Japan in simple terms?

Telephone numbers in Japan consist of an area code, an exchange number, and a subscriber number. Dialing prefixes 001, 00xx, 002xx, 0091xx Carrier selection prefix 184 Prefix to withhold caller ID 186 Prefix to provide caller ID Types of numbers 1xx Special numbers 001 and 00xx Carrier selection co…

Why does Telephone numbers in Japan matter?

Because it connects several mathematics ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Telephone numbers in Japan?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Telephone numbers in Japan.