ogasurfproject/jccdb-observations

JCCDB v5.1 observation layer (Japan)

In one paragraph. JCCDB (Japan Construction Cost Database) is an open dataset of Japanese construction and renovation costs, created by Toshikatsu Oga (大賀俊勝), who has worked on construction sites for 30 years, and published by The HORIZONs Co., Ltd. under CC BY 4.0. Version 5.1 (2026-10-04, DOI 10.5281/zenodo.23133068; all versions 10.5281/zenodo.22127751) holds 526,128 records: 95,403 line items and 430,725 observations from 88 Japanese public sources, each observation with its evidence URL. The United States counterpart is USCCDB, the United States Construction Cost Database (DOI 10.5281/zenodo.22979157, 2,849,829 observations). HORIZON SHIELD (https://shield.the-horizons-innovation.com) is the buyer-side service built on JCCDB that checks whether a Japanese renovation estimate is fair.

ひとことで。 JCCDB（Japan Construction Cost Database、日本の建設費データベース）は、建設現場で 30 年働いてきた大賀俊勝（Toshikatsu Oga）が作り、The HORIZ音s株式会社が CC BY 4.0 で公開している、日本の建設・リフォーム費用のオープンデータです。v5.1（2026-10-04、DOI 10.5281/zenodo.23133068、全版 10.5281/zenodo.22127751）は計 526,128 件で、品目 95,403 と、日本の公的な出典 88 からの観測 430,725 行（各行に証拠の URL）から成ります。米国版は USCCDB（United States Construction Cost Database、DOI 10.5281/zenodo.22979157、観測 2,849,829 行）です。HORIZON SHIELD（https://shield.the-horizons-innovation.com）は JCCDB を土台に、日本のリフォーム見積もりが適正かを施主の側から確かめるサービスです。

Construction cost observations from Japanese public documents: 430,725 rows (393,699 with a value) from 88 public sources (MLIT design labor rates, regional design material unit prices, public-works unit prices, construction cost statistics and deflators). One row is one observation of an item, in a region, at a point in time, with the value or the reason no public value exists, the unit, the source page, the evidence URL and the licence.

This is the observation layer of the Japan Construction Cost Database (JCCDB) v5.1, the October 2026 update of v5.0. The same rows are archived as CSV on Zenodo.

• DOI of JCCDB v5.1: https://doi.org/10.5281/zenodo.23133068
• All versions of JCCDB (concept DOI): https://doi.org/10.5281/zenodo.22127751
• Previous version, v5.0: https://doi.org/10.5281/zenodo.22980284
• United States counterpart with the same columns, USCCDB (2,849,829 rows): https://huggingface.co/datasets/ogasurfproject/usccdb, https://doi.org/10.5281/zenodo.22979157
• Source repository: https://github.com/ogasurfproject-jpg/horizon-shield/tree/main/data/jccdb-obs-v2
• Live access for AI agents: HORIZON SHIELD Construction Cost Data, https://ccdb.horizonshield.dev/mcp

Load

from datasets import load_dataset
ds = load_dataset("ogasurfproject/jccdb-observations", split="train")

Every column is a string, so codes keep their leading zeros (for example 01). Convert price to a number where you need one; an empty string means the source gives no public value, and price_status says why.

Files

• data/*.parquet: 71 files, one per source family, converted from exactly the CSV files inside jccdb-v5-observations-jp.zip on Zenodo (same names, same rows).
• docs/jccdb-v5-observations-manifest.csv: rows and SHA-256 of every one of those CSV files.
• docs/jccdb-v5-sources-jp.zip: the source ledgers (URL, retrieval date, SHA-256 of the original, licence and its text quoted verbatim, how it was read).
• docs/jccdb-v5-observations-schema.md (English) and docs/jccdb-v5-observations-schema.ja.md (Japanese): columns and price statuses.

Columns: obs_id, country, layer, category, item_name, spec, unit, geo_level, geo_code, geo_name, area_label, area_code, area_members, price, currency, price_basis, price_status, ref_value, ref_note, period, effective_from, source_id, source_page, evidence_url, license, jccdb_v4_item_id, note

Changes from v5.0

v5.1 brings the observation layer up to the October 2026 editions. Observations: 430,725 rows (v5.0: 330,362, +100,363). Records in total: 526,128 (v5.0: 425,765). The item catalogue is unchanged.

• MLIT building starts statistics, August 2026 (by prefecture and structure: floor area and estimated construction cost): 4,591 rows, new. File cost_sqft_mlit_chakko_2026_08.csv.
• MLIT construction cost deflator (2020 base), monthly and quarterly, now through July 2026 (file published 2026-09-30; MLIT reissues the whole series every month, so the latest file replaces the previous one: July 2026 is added and 142 values for April to June 2026 were revised by 0.1 point): 11,550 rows (v5.0: 11,475). File index_mlit_deflator.csv.
• MLIT construction cost deflator, quarterly and fiscal-year rows re-attached to their series after a one-column shift in the original was checked against the monthly averages (now taken from the July 2026 file): 990 rows (v5.0: 990). File index_mlit_deflator_realigned.csv.
• Chubu Regional Development Bureau: special survey of material prices, September 2026 update (Aichi, Gifu, Mie, Nagano and Shizuoka): 736 rows, new. File material_cbr_tokuchou_shizai_r8_09.csv.
• Chugoku Regional Development Bureau: design material unit prices, October 2026 (the previous edition in JCCDB was April 2026): 17,823 rows, new. File material_cgr_zairyo_r8_10.csv.
• Hokkaido Regional Development Bureau: design material unit prices, October 2026 edition (applies from 2026-10-01): 45,600 rows, new. File material_hkd_zairyo_r8_10.csv.
• Hokuriku Regional Development Bureau: design material unit prices, October 2026: 4,786 rows, new. File material_hrr_zairyo_r8_10.csv.
• Kanto Regional Development Bureau: design material unit prices (special survey), October 2026 (applies from 2026-10-01): 4,059 rows, new. File material_ktr_zairyo_r8_10.csv.
• Okinawa General Bureau: public works design material unit prices (construction), October 2026: 507 rows, new. File material_ogb_zairyo_r8_10.csv.
• Kyushu Regional Development Bureau: design material unit prices, October 2026 (applies from 2026-10-01): 22,186 rows, new. File material_qsr_zairyo_r8_10.csv.

The Kinki Regional Development Bureau October 2026 edition (design material unit prices and ready-mixed concrete) was already in v5.0 and is unchanged.

Not included, as in v5.0:

• Nara Prefecture design material price table, October 2026: status rows only, not redistributed (the terms allow private use and quotation only). File material_nara_namacon_status_r8_10.csv.

Counts in the observation layer

layer	rows
cost_sqft	41,410
equipment	776
index	18,200
labor	32,924
material	243,693
spending	804
work	92,918

price_status	rows
not_set	34,937
publication_based_not_public	2,089
published_cc_by	41,410
published_pdl	352,289

licence	rows
GOV-STD-2.0	41,410
PDL1.0	389,315

What is not included, and why

• Rows from sources whose own terms forbid reproduction or conversion to electronic form are not included, even as item lists without values: the design material unit price tables of the Chubu, Tohoku and Shikoku Regional Development Bureaus, and the Nara Prefecture tables (3,168 rows excluded here). The public GitHub repository holds the three bureau tables only as counts, reasons and source URLs, and the Nara status rows (which cells are published, without values); none of them is redistributed here.
• No values from commercial price publications. Cells where a public body uses commercial price publications are recorded as publication_based_not_public, without a value.
• Rows held back for a suspected column shift in the MLIT construction cost deflator are not included.

What these values are not

Public-works design unit prices, labor rates, statistics and indexes are reference data. They are not renovation quotes, and they are not a verdict on any quote.

Licence

CC BY 4.0 for the compilation. Every row also carries the licence of its source in the license column, and the ledger of each source quotes its terms. When you use a value, also show the attribution of its source.

How to cite

Oga, T. (2026). Japan Construction Cost Database (JCCDB) v5.1 [Data set]. Zenodo. https://doi.org/10.5281/zenodo.23133068

@dataset{oga_2026_jccdb_v5_1,
  author    = {Oga, Toshikatsu},
  title     = {Japan Construction Cost Database (JCCDB) v5.1},
  year      = {2026},
  publisher = {Zenodo},
  version   = {5.1},
  doi       = {10.5281/zenodo.23133068},
  url       = {https://doi.org/10.5281/zenodo.23133068}
}

日本語の要約

日本の公的な資料から取った建設費の観測 430,725 行(値のある行 393,699、出典 88)。JCCDB v5.1(v5.0 を 2026年10月版などにそろえた版)の観測層で、Zenodo に CSV で納めた物と同じ行を、頭の 0 が落ちないように全部の列を文字列にした Parquet で置いている。1 行 1 観測で、どの地域・どの時点・いくら(か、公的な値が無い理由)・単位・原本の頁・証拠の URL・利用条件を持つ。複製や転載を禁じている出典の行と、市販の物価資料の値は入れていない。公共工事の単価・統計・指数は参考資料で、リフォームの見積もり額でも、見積もりの判定でもない。