Datasets:
The dataset viewer is not available for this split.
Error code: StreamingRowsError
Exception: TypeError
Message: Couldn't cast array of type
struct<太陽光パネルメーカー別品番: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 蓄電池メーカー別品番: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, スイッチ・コンセント品番: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, カーテン・ブラインド全種類: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 舗装材詳細: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 仮設・建設機械リース詳細: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 工事保険・保証費用: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 残土・産廃品目別処分費: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, コンクリート添加剤・特殊材: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 造作家具・オーダー家具: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 植栽・造園資材詳細: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 住宅性能評価・申請費用: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 特殊塗装・防錆・耐熱塗装: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>>
to
{'仮設工事': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '基礎工事': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('float64'), 'memo': Value('string')}), '木構造材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '構造用合板・面材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '金物・ビス・釘': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '断熱材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '屋根材・防水': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '外壁材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '木製建具・サッシ': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '内装下地材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '内装仕上げ材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '水回り設備': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '給排水配管材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '電気配線材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '外構・仕上げ': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '塗装・コーキング材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '資材高騰情報_2026年4月': {'総合指数_2021年比': Value('string'), '直近_2024年12月比': Value('string'), '特に高騰している品目': List(Value('string')), '品薄・納期遅延品目': List(Value('string')), '出典': Value('string')}}
Traceback: Traceback (most recent call last):
File "/src/services/worker/src/worker/utils.py", line 99, in get_rows_or_raise
return get_rows(
^^^^^^^^^
File "/src/libs/libcommon/src/libcommon/utils.py", line 272, in decorator
return func(*args, **kwargs)
^^^^^^^^^^^^^^^^^^^^^
File "/src/services/worker/src/worker/utils.py", line 77, in get_rows
rows_plus_one = list(itertools.islice(ds, rows_max_number + 1))
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/datasets/iterable_dataset.py", line 2690, in __iter__
for key, example in ex_iterable:
^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/datasets/iterable_dataset.py", line 2227, in __iter__
for key, pa_table in self._iter_arrow():
^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/datasets/iterable_dataset.py", line 2251, in _iter_arrow
for key, pa_table in self.ex_iterable._iter_arrow():
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/datasets/iterable_dataset.py", line 494, in _iter_arrow
for key, pa_table in iterator:
^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/datasets/iterable_dataset.py", line 384, in _iter_arrow
for key, pa_table in self.generate_tables_fn(**gen_kwags):
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/datasets/packaged_modules/json/json.py", line 299, in _generate_tables
self._cast_table(pa_table, json_field_paths=json_field_paths),
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/datasets/packaged_modules/json/json.py", line 128, in _cast_table
pa_table = table_cast(pa_table, self.info.features.arrow_schema)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/datasets/table.py", line 2321, in table_cast
return cast_table_to_schema(table, schema)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/datasets/table.py", line 2255, in cast_table_to_schema
cast_array_to_feature(
File "/usr/local/lib/python3.12/site-packages/datasets/table.py", line 1804, in wrapper
return pa.chunked_array([func(chunk, *args, **kwargs) for chunk in array.chunks])
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/local/lib/python3.12/site-packages/datasets/table.py", line 2101, in cast_array_to_feature
raise TypeError(f"Couldn't cast array of type\n{_short_str(array.type)}\nto\n{_short_str(feature)}")
TypeError: Couldn't cast array of type
struct<太陽光パネルメーカー別品番: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 蓄電池メーカー別品番: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, スイッチ・コンセント品番: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, カーテン・ブラインド全種類: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 舗装材詳細: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 仮設・建設機械リース詳細: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 工事保険・保証費用: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 残土・産廃品目別処分費: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, コンクリート添加剤・特殊材: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 造作家具・オーダー家具: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 植栽・造園資材詳細: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 住宅性能評価・申請費用: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>, 特殊塗装・防錆・耐熱塗装: list<item: struct<name: string, unit: string, unit_price: int64, memo: string>>>
to
{'仮設工事': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '基礎工事': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('float64'), 'memo': Value('string')}), '木構造材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '構造用合板・面材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '金物・ビス・釘': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '断熱材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '屋根材・防水': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '外壁材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '木製建具・サッシ': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '内装下地材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '内装仕上げ材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '水回り設備': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '給排水配管材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '電気配線材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '外構・仕上げ': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '塗装・コーキング材': List({'name': Value('string'), 'unit': Value('string'), 'unit_price': Value('int64'), 'standard_qty_30tsubo': Value('int64'), 'memo': Value('string')}), '資材高騰情報_2026年4月': {'総合指数_2021年比': Value('string'), '直近_2024年12月比': Value('string'), '特に高騰している品目': List(Value('string')), '品薄・納期遅延品目': List(Value('string')), '出典': Value('string')}}Need help to make the dataset viewer work? Make sure to review how to configure the dataset viewer, and open a discussion for direct support.
Japan Construction Cost Database (JCCDB)
A public, structured taxonomy of 65,729 construction cost line-items across 398 categories — item names, categories, and units only (no prices).
JCCDB is the first openly published, machine-readable taxonomy of construction and renovation cost line-items for the Japanese market. It is designed to give homeowners, researchers, and developers a neutral, standardized vocabulary for construction cost items — addressing the structural information asymmetry between contractors (who know prices) and homeowners (who do not).
This release contains item names, category classifications, and units of measurement only. It contains no prices. Pricing is intentionally excluded; the database is a naming and classification layer, not a price list.
Abstract
In residential construction and renovation, homeowners face a persistent information asymmetry: estimates are frequently presented as opaque "lump-sum" (一式) line-items with no breakdown of quantity, unit, or unit price. This opacity is a structural enabler of overcharging. A precondition for any neutral cost-verification system is a shared, standardized taxonomy of construction line-items — yet no such open, machine-readable taxonomy has existed for the Japanese market.
The Japan Construction Cost Database (JCCDB) addresses this gap. It is a publicly released taxonomy of 65,729 construction cost line-items organized into 398 categories, specifying for each item its standardized name, category, and unit of measurement. Prices are deliberately excluded; JCCDB defines what is being built and how it is measured, not what it costs. This separation allows the taxonomy to serve as neutral public infrastructure that any party — homeowner, contractor, researcher, or third-party verifier — can reference without commercial bias.
We describe the construction of the taxonomy, its category structure, and its intended role as a foundational layer for transparent cost estimation and consumer-protection applications in the construction domain. The database is released under CC-BY-4.0 and is permanently archived with content-addressed integrity proofs.
Dataset Structure
| Field | Description |
|---|---|
| item name | Standardized name of the construction cost line-item |
| category | One of 398 construction work categories |
| unit | Unit of measurement (e.g., ㎡, m, 個, 式, 人工) |
- Total items: 65,729
- Categories: 398
- Contains prices: No — names, categories, and units only
What this dataset is not
JCCDB is a naming and classification layer. It is intentionally distinct from any pricing dataset. Pricing for HORIZON SHIELD's diagnostic services is maintained in a separate, independent layer ("souba-db", 170 categories) and is not part of this release.
Intended Use
- A standardized vocabulary for describing construction/renovation work
- A classification target for parsing or normalizing real-world estimates
- Research on construction-cost transparency and consumer protection
- A neutral reference layer for third-party cost-verification systems
Out-of-scope / cautions
- This dataset provides no prices and must not be represented as a price reference.
- It does not constitute legal, financial, or construction advice.
Provenance & Permanent Archival
This dataset and its accompanying paper are permanently archived and identified across multiple independent systems for integrity and citation:
| System | Identifier |
|---|---|
| SSRN | abstract_id = 6738701 |
| engrXiv | DOI: 10.31224/7007 |
| Zenodo | (archived) |
| GitHub | ogasurfproject-jpg/japan-construction-cost-database |
| Bitcoin (OpenTimestamps) | Block #949356 |
Content integrity is anchored to the Bitcoin blockchain via OpenTimestamps, providing an independent, tamper-evident proof of the dataset's existence at a fixed point in time.
WPC (Weighted Price Coefficient) reference value: 1.0935 (methodological constant published with the accompanying paper; not a price.)
Citation
If you use this dataset, please cite:
@misc{oga2026jccdb,
title = {Japan Construction Cost Database (JCCDB):
An Open Taxonomy of Construction Cost Line-Items
for Transparency and Consumer Protection},
author = {Oga, Toshikatsu},
year = {2026},
doi = {10.31224/7007},
note = {SSRN abstract 6738701; archived on Zenodo and
Bitcoin block 949356},
howpublished = {Hugging Face Datasets: ogasurfproject/jccdb}
}
License
Released under Creative Commons Attribution 4.0 International (CC-BY-4.0). You may share and adapt the material for any purpose, including commercially, provided you give appropriate credit.
Author
Toshikatsu Oga (大賀 俊勝) Founder & Representative Director, The HORIZ音s株式会社 / HORIZON SHIELD ORCID: 0009-0000-9180-903X 30+ years in construction (carpenter → site supervisor → construction manager → AI engineer)
Project: https://shield.the-horizons-innovation.com/presentation.html
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