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In Japan, a modern legal metrology system was initially established with the enactment of the Law of weights and Measures in 1891. The legal units for measurement were unified into the metric system in 1921, This law was revised into the 1951 Measurement Law. In 1992 the law and related regulations were significantly revised and became effective in 1993 in order to correspond to new social needs, i,e. internationalization, technological innovation, and deregulation. The Measurement Law is supplemented by cabinet orders and ministerial orders.


The new Measurement Law is based on the SI (Systeme international d'Unites) system with limited exceptions for some particular cases, e.g. pound/yardage system for the aerospace area.


3.1 Weights and Measures Office, MITI

The weights and Measures Office of the Machinery and Information Industries Bureau, Ministry of International Trade and Industry (MITI), is in charge of the legal aspects of implementation of the Measurement Law and basic planning for metrology regulation in Japan.

Weights and Measures Office

Machinery and Information Industries Bureau, MITI
l-3-l Kasumigaseki, Chiyoda-Ku, Tokyo 100 Japan
Telephone: +81-3-3501-l688
Fax: +81-3-3580-2768

3.2 Agency of Industrial Science and Technology (AIST), MITI

This agency consists of a secretariat and 15 research laboratories. The National Research Laboratory of Metrology (NRLM) and the EIectrotechnical Laboratory (ETL) are in charge of the pattern approval of measuring instruments and the inspection of verification standards. In addition, the following four research laboratories are responsible for maintaining national primary standards.

3.2.1 National Research Laboratory of Metrology (NRLM), AIST, MITI

The NRLM maintains length, mass, temperature, density, viscosity, humidity, atomic time and frequency, force, hardness, and vibration standards.

1-1-4, Umezono, Tsukuba, Ibaraki 305 Japan
Telephone: +81-298-54-4148
Fax: +81-298-54-4135

3.2.2 Electrotechnical Laboratory (ETL), AIST, MITI

The ETL maintains such primary standards as electric current, electric resistance, voltage, and illuminance.

1-1-4, Umezono, Tsukuba, Ibaraki 305 Japan
Telephone: +81-298-54-5006
Fax: +81 -298-58-5345

3.2.3 National Institute for Materials and Chemical Research (NIMCR), AIST, MITI The NIMCR

controls reference materials in the chemical field and related technology.
1-1, Higashi, Tsukuba, Ibaraki 305 Japan
Telephone: +81-298-54-4411
Fax: +81 -298-54-4639

3.2.4 National Institute for Resources and Environment (NIRE), AIST, MITI The NIRE

controls heat-quantity standard Ibenzoic acid).

16-3, onogawa, Tsukuba, Ibaraki 305 Japan
Telephone: +81-298-58-8103
Fax: +8l -298-58-8208

3.3 International Trade and Industry Inspection Institute (IIII), MITI

The IIII has two basic functions from the metrological point of view. (1) It serves as a secretariat in the calibration laboratory accreditation system and designated manufacturer system which will be explained later. Officers here also work as assessors in the accreditation process. (2) This institute maintains some certified reference materials.

2-49-10 Nishihara, Shibuya-Ku, Tokyo 151 Japan
Telephone: +81-3-3481-1921
Fax: +81-3-3481-1920

3.4 Local verification organisations

To carry out the objectives of the Measurement Law uniformly throughout Japan, there are 47 prefectural verification institutes of weights and measures and 85 municipal inspection institutes of weights and measures.

The main functions of prefectural institutes are to verify legally specified measuring instruments used for trade, to register manufacturers, retailers and repairers of measuring instruments, to inspect weighing instruments periodically, and so on. The main functions of municipal institutes are to inspect weighing instruments periodically and to inspect packaging commodities.

3.5 JEMIC and designated verification institutes

The Japan Electric Meters Inspection Corporation (JEMIC), a non-profit institution established by special law, is responsible for the verification of electricity meters.

In addition, the Measurement Law allows MITI the authority to designate non-profit testing laboratories as designated verification institutes which are obliged to conduct verifications.

The Japan Quality Assurance Institute (JQA) and Japan Gas Appliances Inspection Association have been designated so far. The former institute is responsible for the verification of thermometers, calorimeters, aneroid blood pressure gauges, noise level meters, vibration level meters, and instruments for measuring concentration, while the latter institute is responsible for calorimeters.

3.6 Instrument calibration and evaluation systems

Verification standards used for verification/inspection purposes must check the traceability to the national measurement standards periodically. Instrument calibration services for such verification standards are provided, according to the type of standard, by the NRLM, ETL, JEMIC, and prefectural verification institutes to those institutes or businesses related to regulation.

Calibration services for the private sector not necessarily related to regulation are provided by the calibration laboratory accreditation system stipulated in the new Measurement Law. This accreditation system is referred to as the Japan Calibration Service System (JCSS). (Refer to clause 7.1).


The Measurement Law stipulates the following two restraints concerning the use and supply of certain measuring instruments (referred to as " specified measuring instruments" ) in order to ensure accurate metrology. Containers for specified commodities are also subject to control.

4.1 Specified measuring instruments for trade

Measuring instruments for trade purposes shall not be used unless (1) their design and structure satisfy the pattern requirements and (2) each individual instrument meets the accuracy requirement. The Cabinet Order identifies the following 18 types of instruments as " specified measuring instruments" . Some items were added and some were dropped before and after the new Law, for e.g., digital electric non-automatic weighing instruments with a range between 30 kg and 2t were added to the list while graduated ruler, tape measure, graduated tank, etc. were dropped from the list.

The Measurement Law also requires the manufacturers, repairers and retailers of specified measuring instruments to notify the local weights and measures institutes.(This notification requirement has replaced the registration requirement in the old law).

4.2 Specified measuring instrument for household use

There is another control for those specified measuring instruments used mainly for general household purposes (even though not used for trade or certification). Manufacturers of such instruments are obliged to make their products in compliance with certain technical requirements. Kitchen scales, bathroom scales, and baby scales are subject to this control.

4.3 Special containers

Special containers for the following commodities are allowed to be used for trade by filling the commodities up to a certain height level. The manufacturers of the containers must be designated by MITI as technically proficient and the types of containers must be stipulated by Ministerial Order. Foreign test data issued by MITI approved laboratories are acceptable.


5.1 Legal and technical requirements for pattern approval

MITI is responsible for ensuring that the design of the specified measuring instrument meets certain criteria for accurate measurement. The Minister carries out this responsibility by examining the designs of measuring instruments and testing sample instruments.
Once the pattern of an instrument has been approved, MITI issues a certificate of approval and subsequent production instruments made to the pattern must be marked with an assigned type number. The marking and numbering on a production instrument is the primary indication to the prefectural and other verification institutes that the measuring instrument is of an approved pattern.
Pattern approval is required for all the specified measuring instruments, regardless of type as listed in clause 4.1. Manufacturers, importers, and foreign manufacturers can apply for pattern approval testing of these instruments.

5.2 Execution of pattern approval tests

The authority for pattern approval is delegated to NRLM, ETL and JEMIC. These three institutes carry out the pattern examination according to the type of instrument. (Refer to the list in clause 4.1. Pattern approvals for the instruments marked with 4 are granted by NRLM, with by ETL, by NIRE and with by JEMIC).
NRLM, ETL, NIRE and JEMIC usually examine all the test items specified in the Ministerial Order. However, test data issued by the designated verification institutes (refer to clause 3.5) or by foreign laboratories approved by MITI are acceptable.

5.3 Recognition/acceptance of OIML certificates

Although the revision of the Ministerial Order was made to agree to the greatest possible extent with the OIML recommendations, the technical specifications in Japan are not identical to them. Therefore, the OIML certificates issued in foreign countries are not accepted unconditionally. However, the data for the common test items will be highly respected.
There has been no submission of OIML certificates to the pattern approval authorities in Japan as of January 1995.

5.4 List of major testing facilities for pattern approval

The NRLM, for instance, has the following major testing facilities:

5.5 Fee structure for pattern approval and verification

The fee structure for pattern approval and verification is stipulated in the Cabinet Order as follows:
Type of specified instrument
Type Approval
Weighing instrument
Hide and skin planimeter
Water meter
Pressure-proof density hydrometer
Aneroid pressure gauge
Integrating calorimeter
Maximum demand power meter
Watt-hour meter
Reactive watt-hour meter
Vibration level meter
Glass alcoholometer
Relative density hydrometer


6.1 Verification

Article 16 of the new Measurement Law states that no specified measuring instrument shall be used or owned for the purpose of measurement in a trade or certification without a valid verification mark. A valid verification mark is affixed when an instrument satisfies the type requirements (usually checked by type approval marking) and accuracy requirement stipulated in the Ministerial Order. Verifications are carried out by local institutes, JEMIC and by other designated verification institutes according to type (refer to clauses 3.4 and 3.5).
6.2 Reverification
The Cabinet Order specifies the duration of the validity of a verification mark for certain measuring instruments. In this case, reverifications will be made after required repairs. The following main examples for such instruments are indicated with their duration periods:
Water meter        8 years 
Gas meter         10 years 
Watt-hour meter    7 years 
In addition, the taximeter is subject to reverification after a one year interval. Test items for reverification are identical to the initial verification.

6.3 Periodical inspection

Periodical inspection is a simplified version of reverification. The maximum permissible error for periodical inspection is basically twice as large as that for verification.
Test items for periodical inspection are listed below:
Weighing instrument        2 years 
Hide and skin planimeter   1 year 

6.4 Designated manufacturer

When a manufacturer of specified measuring instruments is designated by MITI as having an excellent quality system and inspection facilities, it may deliver its products after conducting its own self inspection, which replaces official initial verification. This designated manufacturer must also keep inspection records for three years for consequent audit by the local verification institute. The requirement for this designation is stipulated in the Ministerial Order which is basically identical to ISO 9002. Instruments manufactured by such designated manufacturers are still subject to the control of periodical inspection or reverification.
Foreign test data issued by MITI approved institutes are acceptable.


7.1 Calibration laboratory accreditation system

A calibration laboratory accreditation system was established by the new Measurement Law. An accredited calibration laboratory is allowed to provide a calibration certificate marked with JCSS when the laboratory has calibrated a measuring instrument of a general user by its secondary standard calibrated by the national primary standards.
The law specifies that the requirements for accreditation are:

7.2 Quality System accreditation system

The Japan Accreditation Board for Quality System (JAB) is the accreditation body for the accreditation system in Japan. This is a voluntary scheme and therefore there is no formal link with the legal metrology area.


8.1 Staff size of metrological organisations

The following is an approximate number of people involved in the legal metrology area as described above. There is no formal academic requirements but most of the researchers in the research institutes of AIST hold a master degree or higher in the field of science or engineering.
Organization (as of July 1994)
Staff size
Weights and Measures Office
Weights and Measures Training Institute
Prefectural Verification Institutes (47)
Municipal Inspection Institutes (85)

8.2 Training courses for domestic practitioners

Training courses are provided mainly for verifiers and inspectors working in local institutes by the weights and Measures Training Institutes located in the suburban area of Tokyo. No officer can conduct official verification or inspection without completing the appropriate technical training course offered by this Institute. The training courses cover lectures on the Law and the structure of instruments and technical training for verification of measuring instruments.

8.3 Training courses for foreign metrology practitioners

The Japan International Co-operation Agency (JICA) training program has covered the legal metrology area for about twenty years. Training period is about five months accepting six trainees per year. Trainees will have lectures and technical training on type approval, verification and inspection at the NRLM, JEMIC and local institutes. Applicants must have enough English proficiency and experience on legal metrology. More than 250 trainees have completed this course so far and 140 are from Asian countries.

8.4 Measurement certification business

Those who intend to perform the business of measurement certification on the following items must register with the prefectural office.
Measurement certification of length, mass, area, volume or amount of heat of goods at the time of loading, unloading or warehousing of these goods for the purpose of transporting, depositing or selling. (referred to as " general measurement certification" ).
Measurement certification of concentration density of polluted air, water and soil, noise level and vibration level. (referred to as " environmental measurement certification" ).
The registration procedure is completed only when each applicant employs appropriate measuring instruments and at least one certified measurer or an experienced personnel who assumes the responsibility of quality control of the measurement certification activity.
A registered measurement certification business must have periodical measurement certification inspection performed by the local government for all of its registered measuring instruments. When a registered measurement certification business is assumed not to be conforming to requirements above, the prefectural office shall issue an improvement order and force that business to follow it.

8.5 Certified measurer

The Minister may register those having sufficient knowledge and experience to properly perform inspection of measuring instruments and other measurement control as a " certified measurer" .
There are three categories for the registration:

Environmental certified measurer for concentration

: those who deal with measurement of concentration in the air and/or water.

Environmental certified measurer for noise and vibration

: those who deal with measurement of noise and/or vibration levels.

General certified measurer

: those who deal with measurement of quantities other than the above two categories.
The requirement for the registration is either:
Certified measurers can perform inspections which exempt users of weighing instruments and registered measurement certification businesses from mandatory official periodical inspections.


The Measurement Law requires that those who sell certain consumer goods indicating the net content by weight or volume must measure the net content accurately so that the indication and the true value are within a certain permissible error. The Cabinet Order specifies 28 types of consumer goods which should be regulated by this control from the viewpoint of protecting consumers benefits, and therefore such goods are referred to as " specified goods." The specified goods are listed below. Imported specified goods are also under this control.
In addition, certain specified goods, when sold in a sealed package, including milk, cheese, snacks, meat, alcoholic drinks and retort pouch foods must indicate the net content and satisfy the accuracy requirement.
Local governments randomly visit retail shops and check if the indication is within the permissible measurement error. If a retailer of specified goods is regarded as hindering accurate measurement by not abiding by this regulation, the local governments have the right to recommend the retailer, manufacturer and/or importer of the goods satisfy accurate measurement requirement and, if necessary, to consequently publish the name of the retailer and/or manufacturer. The permissible error for extra quantity, which used to be set by the old Measurement Law, has been removed in the new Law to harmonize with the 0IML recommendation.


The main penalties for violating the Measurement Law are as follows:
  1. Delivering a clinical thermometer or an aneroid blood pressure gauge without a verification mark.

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