# Methodology — Japan Akiya & Court-Auction Property Market

**Version:** 2026-09-01 · **License:** CC-BY-4.0 · **Compiled by:** Genkan (arthurbrejon.com/genkan)

## What this is
Aggregate statistics on Japan's vacant-home (*akiya*) and court-foreclosure-auction
property markets, **by prefecture and by city**, in English. It is a derived, aggregate
view — **not** a republication of individual listings, photos, or descriptions.

## Coverage (this version)
- **11,211 listings** aggregated: 9,656 for-sale + 1,555 court auctions.
- **47 prefectures**, **451 cities** (cities with ≥3 listings and a romaji name).
- Price range across all listings: ¥9,000 – ¥608,000,000 (median ¥4,400,000).

## Sources
1. **全国版空き家・空き地バンク** (National Akiya & Vacant Land Bank) — MLIT-subsidised, operated by At Home Co. Voluntary municipal vacant-property listings.
2. **不動産競売物件情報サイト (BIT)** — the Japanese courts' official foreclosure-auction database. Auction prices are court **minimum bids** (売却基準価額), not asking prices.
3. **2023 Housing and Land Survey, Statistics Bureau of Japan (総務省統計局)** — national vacancy context (9,002,000 vacant homes; 13.8% vacancy rate).

## How it's built
Public listing facts (price, address, size, build year, type) are crawled politely, geocoded
(GSI / 国土地理院), normalized, and translated to English, then **aggregated** into the
statistics here. Facts are not copyrightable; we publish only the aggregate, and link to
each source rather than re-hosting photos or prose.

## Field definitions
See `datapackage.json` for the full typed schema. Key fields: `listings` (total),
`for_sale`/`auctions` (split), `price_jpy_min/median/max`, `building_sqm_median`,
`land_sqm_median`, `build_year_median`, `pct_with_photo`.

## Limitations
- A periodic **snapshot**; the live market changes daily.
- Prices mix voluntary asking prices (akiya bank) with court minimum bids (auctions) — the
  `for_sale`/`auctions` columns let you separate them.
- Type classification is inferred; "other" captures unclassified records.
- Cheap auction land (sub-¥100k) is real, not error — court floors can be a few thousand yen.

## Citation
> Genkan (Arthur Brejon). *Japan Akiya & Court-Auction Property Market* [dataset], 2026-09-01. CC-BY-4.0. https://arthurbrejon.com/genkan