Guide
Japan's earthquake building standards: the day work started, the two certificates, and the order that still reaches a building the rules left behind
English writing about buying property in Japan turns on a single year. Three provisions in force today contain that year, and all three turn on something narrower than a year: the day on which work on the new building began. Those three are what this page reports. The cabinet order of 1980 that changed the structural calculation rules is a different provision, it is not served by the database this page was built from, and nothing here describes it. What follows is what the readable provisions say, who decides the questions they leave open, and where the statute hands the work to a qualified professional rather than to a page like this one.
Published 8 September 2026. Statutory text read on 8 September 2026.
Two certificates, issued at different moments
The Building Standards Act (建築基準法, Act No. 201 of 1950) states its own purpose as fixing minimum standards for the site, structure, equipment and use of buildings. Two of its provisions each produce a document, and the two documents are not the same document.
建築主は、…当該工事に着手する前に、その計画が建築基準関係規定…に適合するものであることについて、確認の申請書を提出して建築主事又は建築副主事…の確認…を受け、確認済証の交付を受けなければならない。That is the kakunin-zumisho (確認済証), the confirmation certificate. It is issued before work starts, and what it records is that a plan was found to conform. The official named in the provision is the kenchiku shuji (建築主事), the building official appointed by a municipality or a prefecture to examine plans and to inspect completed work. Article 6-2 allows the same confirmation to be carried out instead by a designated confirmation and inspection body, a private body approved for the purpose.
建築主は、第六条第一項の規定による工事を完了したときは、国土交通省令で定めるところにより、建築主事等の検査…を申請しなければならない。…５検査実施者は、前項の規定による検査をした場合において、当該建築物及びその敷地が建築基準関係規定に適合していることを認めたときは、国土交通省令で定めるところにより、当該建築物の建築主に対して検査済証を交付しなければならない。That is the kensa-zumisho (検査済証), the inspection certificate. It comes after the work, and it records that the building as built, and its site, were found to conform. Article 7(2) gives four days from completion to apply for the inspection, and Article 7(4) gives seven days from receipt of the application to carry it out.
The distinction matters because the two certificates answer different questions. One says a drawing was approved. The other says a building was inspected. A building can have the first without the second, and the Act does not treat the absence of the second as an admission of anything: Article 9, the article on measures against buildings, is worded around a breach of the Act or of a condition attached to a permission under it, not around a missing certificate. What follows from an absent inspection certificate in a particular case is for the tokutei gyoseicho (特定行政庁), which Article 2(xxxv) defines as the head of a municipality that appoints a building official, and otherwise the prefectural governor, with a proviso making it the governor for buildings fixed by cabinet order. That decision rests with that agency, together with the building official and the designated confirmation and inspection body. This page does not predict it.
The provisions that name 1981 name the day work started
The Building Standards Act as in force today contains no year. The date lives in three provisions made under two other statutes — one under the retrofitting Act, two under the Real Estate Brokerage Act — and all three draw the line in the same place. None of the three is the provision that changed the structural rules; each borrows the date for a purpose of its own, and that is the limit of what this section reports.
法第五条第三項第一号の政令で定めるその地震に対する安全性が明らかでない建築物は、昭和五十六年五月三十一日以前に新築の工事に着手したものとする。新築の工事に着手した is the moment work on the new building began. Not the moment a confirmation application was filed, not the moment a confirmation certificate was issued, and not the moment the building was finished or registered. Showa 56, 31 May is 31 May 1981.
The two provisions in the regulation under the Real Estate Brokerage Act use the same test from the other side of the same day. Article 16-4-3(v) excludes 昭和五十六年六月一日以降に新築の工事に着手したもの — a building on which new construction work began on or after 1 June 1981. Article 16-2-3(vi) applies where the home is one on which such work began 昭和五十六年五月三十一日以前に, on or before 31 May 1981.
| Provision | The date it fixes | What it turns on |
|---|---|---|
| Retrofitting order, Art. 3 | On or before 31 May 1981 | The day work on the new building began |
| Brokerage regulation, Art. 16-2-3(vi) | On or before 31 May 1981 | The day work on the new building began |
| Brokerage regulation, Art. 16-4-3(v) | On or after 1 June 1981 (excluded) | The day work on the new building began |
Article 3 of the retrofitting order does not stop at the main clause. Its proviso takes a building back out of the definition where two things happened together: work began, on or after 1 June 1981, on an extension, a reconstruction, a large-scale repair or a large-scale alteration, and an inspection certificate was issued for that work.
A building can have more than one of the independent parts identified in the cabinet order under the Building Standards Act. Where it does, the proviso requires that later work and that inspection certificate for every one of those parts rather than for one of them. Three kinds of work are then excluded from the proviso again, by cross-reference to Article 86-8(1) of the Building Standards Act and to two ranges fixed in the cabinet order under it.
Why the difference is not academic
A registered date of construction and the day work began are different facts recorded in different places, and the provisions above use the second. Which date applies to any particular building, and what evidence establishes it, are questions for the professionals whose statutes cover them. This page identifies the test the provisions use; it does not apply that test to any building.
What the line marks is not knowledge that a building is unsafe
The defined term that Article 3 of the retrofitting order fills in is worth reading closely, because the English word attached to it in conversation is stronger than the Japanese one. Article 5(3)(i) of the Act introduces it inside a bracket, as その地震に対する安全性が明らかでないものとして政令で定める建築物 — a building fixed by cabinet order as one whose safety against earthquakes is not clear. The same bracket shortens that to taishin-fumei kenchikubutsu (耐震不明建築物).
That is a statement about the absence of information, not a finding about a structure. The same paragraph defines a separate term for buildings that do not meet the earthquake provisions: kizon taishin futekikaku kenchikubutsu (既存耐震不適格建築物), which the Act describes as a building that does not conform to the provisions of the Building Standards Act and the orders and ordinances under it relating to safety against earthquakes and that is covered by Article 3(2) of that Act. The two terms are not interchangeable, and the date in the order attaches to the first of them.
What would establish the second, for any actual building, is the work Article 2(1) of the same Act names.
この法律において「耐震診断」とは、地震に対する安全性を評価することをいう。A taishin shindan (耐震診断) is, in the statute's own words, the evaluation of safety against earthquakes. The authority this Act works through is its own. Article 2(3) defines the shokan gyoseicho (所管行政庁), the competent administrative agency, as the head of a municipality or special ward that appoints a building official and otherwise the prefectural governor, again subject to a proviso for buildings fixed by cabinet order. We counted the two terms in each statute at asof=2026-09-08. 特定行政庁 appears 0 times in the retrofitting Act against 44 occurrences of 所管行政庁. The Building Standards Act runs the other way, 270 against 3, and those 3 sit in a single paragraph, Article 15(2), which reaches the definitions in two other statutes rather than making one of its own: Article 2 of the Building Standards Act has no item defining the term. They are separate defined terms in separate statutes, and this page keeps them apart even though the two definitions run along similar lines. Article 23(1) of the Architects Act (建築士法, Act No. 202 of 1950) requires a prefectural governor's registration of an architect office before the survey or appraisal of a building — 建築物に関する調査若しくは鑑定 — is carried on as a business, for reward, at another person's request, and Article 23-10 forbids doing so without it. That is the reason this page describes provisions and stops there.
Lawful but outside the current rules, and the order that still reaches it
Buildings do not have to be rebuilt every time a rule changes. The provision that produces that result is short.
この法律又はこれに基づく命令若しくは条例の規定の施行又は適用の際現に存する建築物若しくはその敷地…がこれらの規定に適合せず、又はこれらの規定に適合しない部分を有する場合においては、当該建築物、建築物の敷地又は建築物若しくはその敷地の部分に対しては、当該規定は、適用しない。A building already standing when a provision came into force or began to apply is simply outside that provision. The word for such a building is kizon futekikaku (既存不適格), and it is not a synonym for an unlawful building. Article 3(3) marks out where the two part company. Its first item withholds the protection from a building that was in breach of the corresponding earlier provision: a building that broke the rules of its own day never gained the exemption, and cannot acquire it by growing older.
Being outside a provision is also not immunity. Article 10 is drafted so that it reaches only the buildings Article 3(2) leaves outside the rules.
特定行政庁は、第六条第一項第一号に掲げる建築物その他政令で定める建築物の敷地、構造又は建築設備（いずれも第三条第二項の規定により次章の規定…の適用を受けないものに限る。）について、損傷、腐食その他の劣化が進み、そのまま放置すれば著しく保安上危険となり…おそれがあると認める場合においては、…相当の猶予期限を付けて、当該建築物の除却、移転、改築、増築、修繕、模様替、使用中止、使用制限その他保安上又は衛生上必要な措置をとることを勧告することができる。A recommendation under Article 10(1) can become an order under Article 10(2) where it is not followed without justification, and Article 10(3) allows an order directly where the building is found to be seriously unsafe. The procedural safeguards in Article 9(2) to (9) and (11) to (15) — the written notice, the chance to submit a written opinion and evidence, the public hearing that may be requested within three days — are applied to those cases by Article 10(4). Whether any of this applies to a particular building is for the designated administrative agency, and this page does not say.
What later work does to the exemption
Article 3(3) has a third item, and it is the one that changes what a renovation means. It withholds the Article 3(2) protection from an extension, a reconstruction, a relocation, a large-scale repair or a large-scale alteration where the work started after the provision came into force or began to apply. Article 2(xiv) and (xv) define the last two: a large-scale repair is the repair of more than half of one or more of the principal structural parts, and a large-scale alteration is the alteration of more than half of one or more of them. Article 2(v) lists those parts as walls, columns, floors, beams, roofs and stairs, and then excludes a long list of items that are not structurally important.
Article 86-7 then relaxes that, but only inside limits. Its first paragraph disapplies Article 3(3) for extensions and similar work carried out within a range fixed by cabinet order, over a long list of articles that includes Article 20 — and for Article 20 it adds a condition in brackets: where a building outside Article 20 by virtue of Article 3(2) is extended or reconstructed within that range, the relaxation applies only if the structural method of the building after the work conforms to a standard fixed by cabinet order. Article 86-7(2) deals with buildings that have two or more independent parts, and leaves the provisions disapplied for the parts not being worked on.
The same idea appears in the retrofitting order
The proviso in Article 3 of the retrofitting order, set out above, is built from the same two ingredients: later work of one of those four kinds, plus an inspection certificate for it. The two statutes are not saying the same thing — one is about which rules apply, the other about which buildings the retrofitting Act treats as being of unclear safety — but both attach consequences to major work rather than to the passage of time.
What an agent must say, and what the duty stops short of
The word 耐震 does not appear anywhere in the Real Estate Brokerage Act (宅地建物取引業法, Act No. 176 of 1952). We searched its full text at asof=2026-09-08 and found no occurrence. The duty is in the ministerial regulation, under the catch-all in Article 35(1)(xiv)(a), and its shape is narrower than the word “duty” suggests.
当該建物（昭和五十六年六月一日以降に新築の工事に着手したものを除く。）が建築物の耐震改修の促進に関する法律第四条第一項に規定する基本方針のうち同条第二項第三号の技術上の指針となるべき事項に基づいて次に掲げる者が行う耐震診断を受けたものであるときは、その内容The operative words are 受けたものであるときは、その内容: where the building has had such an evaluation, its content is explained. The provision creates no duty on anyone to obtain an evaluation, and where none exists there is nothing under this item to explain. The four kinds of person whose evaluation counts are listed in the same item: a designated confirmation and inspection body under Article 77-21(1) of the Building Standards Act, an architect, a registered housing performance evaluation body under Article 5(1) of the Housing Quality Assurance Act, and a local public body.
A second item reaches the paperwork itself. Article 35(1)(vi)-2(b) of the Act requires, for an existing building, an explanation of the state of keeping of documents fixed by ministerial order, and Article 16-2-3 of the regulation lists six of them.
| Item | The document |
|---|---|
| (i) | The confirmation application, the plan notification, and the confirmation certificate |
| (ii) | The inspection certificate |
| (iii) | The report on the result of a building condition investigation |
| (iv) | The construction housing performance evaluation report for an existing home |
| (v) | Documents under Arts. 5(3) and 6(3) of the regulation under the Building Standards Act |
| (vi) | Where new construction work on the home began on or before 31 May 1981: documents evidencing conformity with the earthquake provisions, or something equivalent — a seismic evaluation report by an architect, a construction housing performance evaluation report, evidence that an insurance contract under Art. 19(ii) of the Act on Assurance of Performance of Specified Housing Defect Warranty has been concluded in relation to the sale of the existing home, or other documents on the seismic performance of the home |
Again the duty is about keeping, not about existence. The explanation records the state of the documents; it does not require that any of them be produced, and it does not turn their absence into a defect.
The building condition investigation, in three separate places
The Real Estate Brokerage Act sets out one more mechanism, and it does so across three articles that do three different things. The definition sits in the first of them.
当該建物が既存の建物であるときは、依頼者に対する建物状況調査（建物の構造耐力上主要な部分又は雨水の浸入を防止する部分として国土交通省令で定めるもの…の状況の調査であつて、経年変化その他の建物に生じる事象に関する知識及び能力を有する者として国土交通省令で定める者が実施するものをいう。…）を実施する者のあつせんに関する事項- Article 34-2(1)(iv) — the brokerage agreement. Where the building is an existing one, the written agreement between the agent and the person instructing them must cover the arranging of someone to carry out a tatemono jokyo chosa (建物状況調査). The item is about arranging, not about carrying out.
- Article 35(1)(vi)-2(a) — the explanation of important matters. Whether an investigation has been carried out, limited to one where the period fixed by ministerial order has not yet passed, and where it has, the outline of its result.
- Article 37(1)(ii)-2 — the contract document. Where the building is an existing one, what both parties confirmed about the condition of the structurally important parts and the parts that keep rainwater out.
The three are worth separating because they run at different moments and attach to different documents: one at instruction, one before the contract, one in the contract. The investigation itself is carried out by a person fixed by ministerial order as having the knowledge and ability regarding ageing and other phenomena occurring in buildings. It is a different exercise from the seismic evaluation defined in Article 2(1) of the retrofitting Act, and the statutes keep them apart.
Who is actually required to have an evaluation carried out
The retrofitting Act arranges buildings into three tiers, and only the first carries a duty backed by a reporting deadline.
| Tier | Provision | What the Act requires |
|---|---|---|
| Buildings written into a prefectural or municipal retrofitting plan | Art. 7 | The owner must have a seismic evaluation carried out and report the result to the competent administrative agency by the deadline written into that plan. |
| The listed categories at the listed sizes | Art. 14 | The owner must endeavour to have a seismic evaluation carried out and, where its result shows that safety against earthquakes needs to be improved, to carry out retrofitting. The provision is a single effort duty covering both steps, built the same way as Art. 16. |
| Every other existing building that does not meet the earthquake provisions | Art. 16 | The owner must endeavour to have an evaluation carried out and, as necessary, to carry out retrofitting. The competent administrative agency may give guidance and advice. |
Article 6 of the retrofitting order fills in the second tier. Its first paragraph lists eighteen categories of what Article 14(i) of the Act calls a building 多数の者が利用する — used by a large number of people — bowling alleys and other sports facilities, clinics, cinemas, public halls, markets and shops, hotels and inns, rental housing limited to apartment buildings, welfare facilities, museums, amusement facilities, public baths, restaurants, service businesses including banks, factories, transport buildings, car and bicycle parking facilities, and public-interest buildings such as health centres and tax offices. Its second paragraph then fixes the size at which each of them is caught, in storeys and total floor area.
| Category | Storeys | Total floor area |
|---|---|---|
| Kindergartens, integrated centres for early childhood education and care, and nurseries | 2 | 500 m² |
| Schools at the compulsory-education stages and the corresponding special-needs schools, homes for the elderly, and the welfare categories at items (viii) and (ix) other than nurseries | 2 | 1,000 m² |
| Other schools, hospitals, theatres, spectator facilities, halls, exhibition halls, department stores, offices, and the categories at items (i) to (vii) and (x) to (xviii) | 3 | 1,000 m² |
| Gymnasiums | 1 | 1,000 m² |
Two readings follow from the wording, and both are about which provision a building sits under rather than about any building in particular. Item (vii) of that list is rental housing limited to apartment buildings, so a block of flats held for letting is inside the second tier at three storeys and 1,000 square metres, while housing that is not rental housing is not caught by item (vii) at all. And the third tier, Article 16, is written as an effort duty for the owner, with the competent administrative agency's role confined to guidance and advice. Nothing in the Act obliges the owner of an ordinary home to obtain an evaluation.
A building in divided ownership, and the mark in advertising
Article 25 of the retrofitting Act is written for a building in kubun shoyu (区分所有) — divided ownership, the legal structure under which a block of flats is split among separate owners who hold the common elements together. Where a seismic evaluation has been carried out, the manager or the board may apply to the competent administrative agency for a certification that retrofitting is necessary, and that agency may grant it where the building does not meet the standard the minister fixes as equivalent to the earthquake provisions.
What the certification changes is the vote. Article 25(3) provides that, where the retrofitting of a certified building amounts to a change to the common elements under Article 17(1) of the Act on Building Unit Ownership, the special-majority wording in Article 17(1) and in Article 17(3) is read instead as 集会の決議 — a resolution of the meeting — and Article 17(5) does not apply. The threshold written into the unit-ownership provision is replaced; it is not merely lowered by a stated fraction, and the substituted words are the ones quoted here.
Article 22 runs the other way, and is about what may be said. Under Article 22(1) an owner may apply for a certification that the building conforms to the earthquake provisions, or to the standard the minister fixes as equivalent for that purpose. Article 22(3) then lets the holder put a mark to that effect on advertising and other matter fixed by ministerial order — and Article 22(4) closes the loop.
何人も、前項の規定による場合を除くほか、建築物、その敷地又はその利用に関する広告等に、同項の表示又はこれと紛らわしい表示を付してはならない。何人も is “no person”. Outside the certification, that mark, and any mark confusingly similar to it, may not be attached to advertising about a building, its site or its use.
The ten years that attach only to a new home
The Housing Quality Assurance Act (住宅の品質確保の促進等に関する法律, Act No. 81 of 1999) contains a ten-year liability for defects in the structurally important parts and the parts that keep rainwater out. Article 94(1) places it on the contractor towards the client under a contract to build a home; Article 95(1) places it on the seller towards the buyer under a contract for the sale of a new home. Both run from delivery, and Articles 94(2) and 95(2) void a term that is worse for the client or the buyer.
The reach of those articles is set by a definition three chapters earlier.
この法律において「新築住宅」とは、新たに建設された住宅で、まだ人の居住の用に供したことのないもの（建設工事の完了の日から起算して一年を経過したものを除く。）をいう。A shinchiku jutaku (新築住宅) is a newly built home that has not yet been lived in, and the bracket excludes one where a year has passed since the construction work was completed. A home that falls outside that definition falls outside Articles 94 and 95, and what liability a seller has instead is a question of the Civil Code and of the contract, which this page does not address.
The three notifications of 2000 for timber houses, and the one that no longer exists
The second date in English writing about Japanese houses is 2000, and it belongs to a different layer of the law. The Building Standards Act sends the structural detail to a cabinet order, and three provisions of that order send it on again to the minister.
建築物の基礎の構造は、建築物の構造、形態及び地盤の状況を考慮して国土交通大臣が定めた構造方法を用いるものとしなければならない。… 階数が二以上又は延べ面積が五十平方メートルを超える木造の建築物においては、第一項の規定により配置する軸組は、…国土交通大臣が定めた構造方法を用いるもの又は国土交通大臣の認定を受けたものを、…国土交通大臣が定める基準に従つて設置するものでなければならない。… 構造耐力上主要な部分である継手又は仕口は、ボルト締、かすがい打、込み栓打その他の国土交通大臣が定める構造方法によりその部分の存在応力を伝えるように緊結しなければならない。Three ministerial notifications of 2000 fill those three gaps. e-Gov does not serve notifications, so we read them from the copies the Ministry of Land, Infrastructure, Transport and Tourism publishes on its own site. Each of the three closes with a one-line supplementary provision, この告示は、平成十二年六月一日から施行する。 — in force from 1 June 2000. The date English writing attaches to timber houses is that enforcement date, and it appears nowhere in the disclosure provisions described above, which carry only 1981.
| Notification | Provision it fills | What it fixes | Status on 8 September 2026 |
|---|---|---|---|
| Ministry of Construction Notification No. 1347 of 23 May 2000 (建築物の基礎の構造方法及び構造計算の基準を定める件) | Order Art. 38(3) and (4) | Which foundation types may be used, by the ground's long-term allowable bearing capacity: below 20 kN/m², piles; from 20 to below 30, piles or a raft foundation (べた基礎); 30 and above, piles, a raft or a strip foundation (布基礎). Exceptions for tea houses, sheds within 10 m², gates and fences, and certain timber buildings on ground of 70 kN/m² or more. Then the specification for each type, and the calculation route. | In force. The National Diet Library index lists six amending notifications, the latest No. 215 of 27 March 2025. |
| Ministry of Construction Notification No. 1352 of 23 May 2000 (木造建築物の軸組の設置の基準を定める件) | Order Art. 46(4) | The balance check on bracing walls. For each storey and each direction, take the outer quarter at each end of the plan (側端部分), compute the wall quantity present and the wall quantity required, divide to get a sufficiency ratio for each end, and confirm that the smaller ratio divided by the larger is 0.5 or more — unless both ends exceed 1, or an eccentricity of 0.3 or less is confirmed by calculation. | Abolished with effect from 1 April 2025 by Notification No. 447 of 31 May 2024, its content moved into Notification No. 1100 of 1981, which was renamed 木造の建築物の軸組の構造方法及び設置の基準を定める件. The Ministry's circular of 27 June 2024 states this in terms. |
| Ministry of Construction Notification No. 1460 of 31 May 2000 (木造の継手及び仕口の構造方法を定める件) | Order Art. 47(1) | Item (i): the joint at each end of a brace, by the type of brace, or a joint of equal or greater tensile capacity. Item (ii): the joint at the top and the foot of a column in a braced frame, chosen from tables by the type of frame and the column's position — unless the tensile force at that joint is confirmed not to exceed the joint's capacity. Item (iii): every other structural joint, by bolting, cramping, pegging or another method that carries the force present. | In force. The National Diet Library index lists five amending notifications, the latest No. 1005 of 9 July 2024. |
Two cautions attach to that table, and both are about what we read rather than about any building. The copies on the Ministry's site were posted in 2017, and they have not been checked against the Official Gazette of 2000: the copy of No. 1352 carries a 2007 amendment on its face, while the amendment histories for No. 1347 and No. 1460 begin after the copies were posted. So the requirements described are the requirements as those copies state them, and the enforcement date is quoted from the supplementary provision printed in each copy. And Article 46(4) of the order, the provision that No. 1352 filled, reaches timber buildings of two or more storeys or over 50 square metres; what any of this meant for a particular house is a question about that house, which this page does not ask.
Why a notification can disappear while the rule does not
A notification is the minister's instrument, and the minister can withdraw it and restate its content in another instrument without the Act or the cabinet order changing. That is what happened to No. 1352 on 1 April 2025: the delegation in Article 46(4) of the order is still there, and the balance check is now stated in the renamed Notification No. 1100. A search for the 2000 number alone would suggest the check had gone. It has not; it has moved.
What changed on 1 April 2025, measured against the earlier text
The categories in Article 6(1) — the ones that decide which buildings need a confirmation at all, and which may use the shortcut in Article 6-4 — were rewritten with effect from 1 April 2025 by Act No. 69 of 2022. We read Article 6, Article 6-4 and Article 20 at asof=2025-03-31, which e-Gov served as revision 325AC0000000201_20241101_506AC0000000053, and again at asof=2025-04-01, served as 325AC0000000201_20250401_504AC0000000069. The comparison below is our own reading of those two texts.
| Article 6(1) | Text served for 31 March 2025 | Text served for 1 April 2025 |
|---|---|---|
| Item (i) | Special buildings in the uses listed in Appended Table 1, column (i), over 200 m² in the floor area used for that purpose | Unchanged |
| Item (ii) | Timber buildings of three or more storeys, or over 500 m², or over 13 m in height, or over 9 m to the eaves | Any building, other than one in item (i), with two or more storeys or over 200 m² |
| Item (iii) | Non-timber buildings of two or more storeys, or over 200 m² | The catch-all for buildings inside city planning areas and the other designated areas (previously item (iv)) |
| Item (iv) | The catch-all for buildings inside city planning areas and the other designated areas | No longer present — the list ends at three items |
Two consequences follow from the wording, and both are readable from the texts themselves. The first is that the separate, more generous thresholds for timber buildings are gone: after 1 April 2025 the second item is stated without reference to the material, so a two-storey house sits in item (ii) whatever it is built from, whereas a two-storey timber house of 200 to 500 square metres sat in the catch-all before. The second is what that does to Article 6-4.
| Article 6-4(1)(iii) | Text served for 31 March 2025 | Text served for 1 April 2025 |
|---|---|---|
| Which buildings may use the confirmation shortcut | 第六条第一項第四号に掲げる建築物で建築士の設計に係るもの | 第六条第一項第三号に掲げる建築物で建築士の設計に係るもの |
The shortcut still points at the catch-all category designed by an architect; the number moved from (iv) to (iii) because the list above it shrank. What changed is not the shortcut but the population inside the category it points to. Article 6-4(1) works by rewriting a phrase in Article 6(1) so that the building standards provisions fixed by cabinet order are excluded from what is examined, and Article 6-4(2) tells the cabinet order to fix only provisions whose omission from the examination is found to raise no problem of safety, fire safety or sanitation, having regard to the technical level of architects and to the site, structure and use of buildings.
Article 20(1) was restructured in the same amendment. In the text served for 31 March 2025, its second tier was defined by cross-reference to the items of Article 6(1) and by a height of over 13 metres or eaves over 9 metres. In the text served for 1 April 2025, the same tier is stated directly: timber buildings of four or more storeys above any basement, or over 16 metres in height, and non-timber buildings meeting the steel, reinforced concrete and other thresholds already there. The third tier now names, for timber buildings, three or more storeys above any basement or a total floor area over 300 square metres.
What we did not measure
The technical content behind Article 20 is in the cabinet order and in ministerial notifications, and this page compares only the text of the Act. What difference any of this makes to a particular building is not something the statutory text answers, and it is not answered here.
What this page does not settle
Four things could not be established, and are recorded rather than filled in.
- The 1980 cabinet order itself was not read. e-Gov's law data service refuses an
asofearlier than 1 April 2017. We tried 1981-06-01 and 2017-03-31 on 8 September 2026 and both were refused with the message that the date must be 2017-04-01 or later; 2017-04-01 was accepted and returned revision 325AC0000000201_20160901_428AC0000000072. So this page says nothing about what the amending order of 1980 provided, or about the date rule it used. What it reports is the test used by the three provisions in force today that contain the date. - Only three notifications were read, from the Ministry's copies. A search of the same service by law number for 平成十二年建設省告示第千四百六十号 returned a total count of 0 on 8 September 2026: notifications are not served by the current-law database. The three notifications of 2000 described above were read from the copies on the Ministry's website, which were not checked against the Official Gazette, and their amendment histories from the National Diet Library's index. Every other notification, including the renamed No. 1100 that now carries the balance check, was not read.
- No case law was read. Every statement here is a reading of statutory, cabinet order and ministerial order text. How that text applies to an actual building is decided by the authorities named in it and, where it is disputed, by the courts.
- Local rules were not surveyed. Prefectural and municipal retrofitting plans under Articles 5 and 6 of the retrofitting Act decide which buildings fall into the first tier above, and ordinances, subsidies and tax measures differ from one place to the next. None of them was examined.
Sources
Every statutory text below was read on 8 September 2026 through the e-Gov law search service maintained by Japan's Digital Agency, at the version in force on that date, except where a different asof date is stated because the point being made is a change between two versions. Where a date, a count or a comparison is our own measurement rather than something printed in a source, we say so both here and in the body.
Building Standards Act (建築基準法), Act No. 201 of 1950 — Arts. 2, 3, 6, 6-4, 7, 9, 10, 12, 20, 86-7
Read at asof=2026-09-08, at the revision e-Gov labels 325AC0000000201_20260527_508AC0000000023. Art. 2(xiv) and (xv) define a large-scale repair and a large-scale alteration. Art. 3(1) lists the buildings the Act does not reach at all; Art. 3(2) is the provision that leaves an existing building outside a rule that came in after it; Art. 3(3) lists the five cases in which Art. 3(2) does not apply. Art. 6(1) provides for the confirmation and the confirmation certificate, across three categories. Art. 6-4(1)(iii) is the confirmation shortcut for the third category where an architect designed the building. Art. 7(1) to (5) are the completion inspection and the inspection certificate. Art. 9 is the measures against a building that breaches the Act. Art. 10 is the recommendation and the order against a seriously unsafe building, and its bracket restricts it to buildings that Art. 3(2) leaves outside the rules. Art. 12(1) is the periodic report by an architect or a qualified building investigator. Art. 20(1) is the structural strength requirement and its four tiers. Art. 86-7(1) relaxes the loss of Art. 3(2) protection for work within a range fixed by cabinet order. We also read Arts. 6, 6-4 and 20 at asof=2025-03-31 and asof=2025-04-01; the comparison in the body is our own measurement of those two texts.
Order for Enforcement of the Building Standards Act (建築基準法施行令), Cabinet Order No. 338 of 1950
Read at asof=2026-09-08, at the revision e-Gov labels 325CO0000000338_20251201_507CO0000000377. This order carries the technical standards that Arts. 20 and 86-7 of the Act leave to a cabinet order, and it is the order that Art. 3 of the retrofitting order cross-references for independent parts of a building and for the ranges of work it excludes. This page states no technical standard from it.
Read at asof=2026-09-08, at the revision e-Gov labels 407AC0000000123_20260401_507AC0000000047. Art. 2(1) defines a seismic evaluation as evaluating safety against earthquakes, Art. 2(2) defines seismic retrofitting, and Art. 2(3) defines the competent administrative agency (所管行政庁) — a defined term of this Act, distinct from the designated administrative agency (特定行政庁) defined in Art. 2(xxxv) of the Building Standards Act. We counted both terms in both Acts at asof=2026-09-08: 特定行政庁 appears 0 times in the retrofitting Act and 270 times in the Building Standards Act, while 所管行政庁 appears 44 times in the retrofitting Act and 3 times in the Building Standards Act, all three of those in Art. 15(2) and all three referring to the definition in another statute rather than making one. Art. 5(3)(i) defines an existing building that does not meet the earthquake provisions and is covered by Art. 3(2) of the Building Standards Act, and introduces the defined term for a building whose safety is not clear. Art. 7 is the duty to have an evaluation carried out and report it, and it reaches only buildings written into a prefectural or municipal plan. Art. 14 is the effort duty for the listed categories at the sizes fixed by order. Art. 16 is the effort duty for everything else. Art. 17 is the certification of a retrofitting plan. Art. 22 is the certification that a building meets the earthquake provisions, with Art. 22(3) allowing the mark in advertising and Art. 22(4) forbidding that mark, or a mark confusingly similar to it, to anyone else. Art. 25 is the certification for a building in divided ownership.
Read at asof=2026-09-08, at the revision e-Gov labels 407CO0000000429_20250401_506CO0000000172. Art. 3 fixes the date that the Act's defined term for a building of unclear safety turns on, and adds a proviso taking a building back out where later work began on or after 1 June 1981 and an inspection certificate was issued. Art. 6(1) lists the eighteen categories of building answering to 多数の者が利用する in Art. 14(i) of the Act, item (vii) being rental housing limited to apartment buildings, and Art. 6(2) fixes the storey counts and floor areas at which each category is caught.
Real Estate Brokerage Act (宅地建物取引業法), Act No. 176 of 1952 — Arts. 34-2, 35, 37
Read at asof=2026-09-08, at the revision e-Gov labels 327AC1000000176_20260401_507AC0000000068. Art. 34-2(1)(iv) puts the arranging of a building condition investigation into the written brokerage agreement and defines that investigation. Art. 35(1)(vi)-2 is the pair of items for an existing building: sub-item (a) whether an investigation has been carried out and the outline of its result, sub-item (b) the state of keeping of the documents fixed by ministerial order. Art. 35(1)(xiv)(a) is the catch-all that the seismic evaluation item sits under. Art. 37(1)(ii)-2 puts what both parties confirmed about the structurally important parts into the contract document. The word 耐震 does not appear anywhere in this Act: we searched the full text and found no occurrence.
Read at asof=2026-09-08, at the revision e-Gov labels 332M50004000012_20260401_507M60000802002. Art. 16-2-3 lists the six kinds of document whose state of keeping is explained under Art. 35(1)(vi)-2(b): (i) the confirmation application and the confirmation certificate, (ii) the inspection certificate, (iii) the building condition investigation report, (iv) the construction housing performance evaluation report for an existing home, (v) documents under Arts. 5(3) and 6(3) of the regulation under the Building Standards Act, and (vi), where new construction work on the home began on or before 31 May 1981, documents evidencing conformity with the earthquake provisions. Art. 16-4-3(v) is the seismic evaluation item: it excludes a building on which new construction work began on or after 1 June 1981, and it applies where the building has had an evaluation carried out by a designated confirmation and inspection body, an architect, a registered housing performance evaluation body or a local public body.
Read at asof=2026-09-08, at the revision e-Gov labels 419AC0000000066_20251001_505AC0000000053. Art. 19 lists the business of an insurance corporation under this Act, and item (ii) is the underwriting of insurance contracts, other than the statutory housing defect warranty insurance contracts of item (i), covering losses arising from the defect liability provisions of the Civil Code. Art. 16-2-3(vi)(c) of the brokerage regulation names an item (ii) contract concluded in relation to the sale of an existing home. We read this article only to render that cross-reference correctly, and this page states nothing else about the Act.
Architects Act (建築士法), Act No. 202 of 1950 — Arts. 23, 23-10, 34
Read at asof=2026-09-08, at the revision e-Gov labels 325AC1000000202_20260731_508AC1000000074. Art. 23(1) requires a prefectural governor's registration of an architect office before design, construction supervision, work on construction contracts, direction and supervision of construction, the survey or appraisal of a building, or agency in procedures under building law is carried on as a business, for reward, at another person's request. Art. 23-10 forbids carrying on that business without the registration. Art. 34 forbids anyone who is not an architect to use the title or a title confusingly similar to it. These provisions are why this page describes provisions and does not look at buildings.
Housing Quality Assurance Act (住宅の品質確保の促進等に関する法律), Act No. 81 of 1999 — Arts. 2, 94, 95
Read at asof=2026-09-08, at the revision e-Gov labels 411AC0000000081_20250601_504AC0000000068. Art. 2(2) defines a new home as one newly built, not yet lived in, and excluding one where a year has passed since the completion of the construction work. Art. 94(1) gives the contractor a ten-year liability to the client for defects in the structurally important parts and the parts that keep rainwater out, and Art. 94(2) voids a term worse for the client. Art. 95(1) gives the buyer the same ten years against the seller of a new home, and Art. 95(2) voids a term worse for the buyer.
Read on 8 September 2026, extracted to text with a PDF library and read in full. Made under Art. 38(3) and (4) of the cabinet order. It has two headed parts: 第一, the structural method for foundations, whose opening text assigns foundation types by bearing capacity and lists three exceptions, and 第二, the basis for structural calculation of foundations. The description in the table above is our own summary of 第一. Each copy opens by naming the provision of the cabinet order it is made under and closes with the supplementary provision この告示は、平成十二年六月一日から施行する。 The copies sit in a folder the Ministry labels 201703 and the PDF metadata gives a creation date in March 2017. Whether a copy matches the text as made in 2000 has not been checked against the Official Gazette: the copy of No. 1352 shows a 2007 amendment on its face, while the first amendments the National Diet Library lists for No. 1347 and No. 1460 both fall after March 2017.
Read on 8 September 2026 in the same way. Made under Art. 46(4) of the cabinet order, and set out in three items, 一 to 三, which the table above summarises. The copy carries the line 改正 平成一九年九月二七日国土交通省告示第一二二七号 under its title. This notification has since been abolished; see the National Diet Library entry and the Ministry's circular below. Each copy opens by naming the provision of the cabinet order it is made under and closes with the supplementary provision この告示は、平成十二年六月一日から施行する。 The copies sit in a folder the Ministry labels 201703 and the PDF metadata gives a creation date in March 2017. Whether a copy matches the text as made in 2000 has not been checked against the Official Gazette: the copy of No. 1352 shows a 2007 amendment on its face, while the first amendments the National Diet Library lists for No. 1347 and No. 1460 both fall after March 2017.
Read on 8 September 2026 in the same way. Made under Art. 47(1) of the cabinet order, and set out in three items, 一 to 三, with three tables; the table above summarises the three items. Each copy opens by naming the provision of the cabinet order it is made under and closes with the supplementary provision この告示は、平成十二年六月一日から施行する。 The copies sit in a folder the Ministry labels 201703 and the PDF metadata gives a creation date in March 2017. Whether a copy matches the text as made in 2000 has not been checked against the Official Gazette: the copy of No. 1352 shows a 2007 amendment on its face, while the first amendments the National Diet Library lists for No. 1347 and No. 1460 both fall after March 2017.
Read on 8 September 2026. The entry for No. 1460 (lawId 0000087139) lists amendments by Notification No. 867 of 26 September 2017, No. 490 of 26 March 2018, No. 203 of 25 June 2019, No. 447 of 31 May 2024 and No. 1005 of 9 July 2024, and shows it in force. The entry for No. 1347 (lawId 0000087014) lists amendments by No. 813 of 4 September 2017, No. 1098 of 12 September 2018, No. 203 of 25 June 2019, No. 592 of 27 May 2022, No. 1005 of 9 July 2024 and No. 215 of 27 March 2025, and shows it in force. The entry for No. 1352 (lawId 0000087023) lists one amendment, No. 1227 of 27 September 2007, and records its abolition by Notification No. 447 of 31 May 2024 with effect from 1 April 2025. None of the three entries states an enforcement date; that date is taken from the copies above.
Read on 8 September 2026. The circular states that Notification No. 447 of 31 May 2024 was promulgated on that date and comes into force on 1 April 2025, and, in its section on Art. 46, that No. 1351 and No. 1352 of 2000 were abolished, that the standards they carried under Art. 46(4) of the order were placed in No. 1100 of 1981, and that the title of No. 1100 was amended to 木造の建築物の軸組の構造方法及び設置の基準を定める件. The renamed No. 1100 itself was not read.
e-Gov law search API, version 2 — what it would not give us
Measured on 8 September 2026. An asof earlier than 1 April 2017 is refused with the message that asof must be 2017-04-01 or later; we tried 1981-06-01 and 2017-03-31 and both were refused, while 2017-04-01 was accepted. A law_num search for 平成十二年建設省告示第千四百六十号 returned total_count 0. So the cabinet order of 1980 that changed the structural calculation rules, and the ministerial notifications that carry the technical detail for timber houses, could not be read, and this page states nothing about their content.
A note on what this page deliberately leaves out
SHINWA CREATIVE, K.K. is a welding and metalwork company in Miyagi Prefecture. Work that strengthens buildings is work the company could be paid for, so no method, product, fitting, cost or contractor is named anywhere above, and nothing here is an offer or a solicitation of any work. The same reasoning keeps prices, values and insurance off the page entirely.
Article numbers make for slow reading, and this one asked for a lot of them across six statutes. Our thanks to everyone who spent the time it takes to reach the end of a page built this way.