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The Supreme Court of Japan publishes the case law the courts select for their reports: the Supreme Court’s own judgments and decisions, the high courts’ reports, the lower courts’ bulletin and the collections of administrative, labour and intellectual property cases, about 68,000 rulings since 1947. Each one here comes with its case number and name, the court and bench, the date, the kind of decision and its outcome, the lower court’s decision, the court’s own summary and the statutes it cites where the court publishes them, the full text read from the court’s document, the document itself as the court published it, and a link to its page at the courts. Search across every collection at once, by collection, court, case number, year or date, or with free text in Japanese that reaches into the summaries and the body of every ruling.
The whole source, organized and ready to query: every endpoint on this page answers in milliseconds. Every response carries as_of: how current the data is. How datasets work.

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Search the rulings

POST /jp/courts-jp/rulings-search/v1 Dataset One search over every collection of the courts’ case law since 1947, filtered by collection, court, case number, year or date.
Returns as_of (how current the data is), the applied filters, total and total_is_exact, page, per_page, total_pages, count and results[], most recent ruling first. Every result carries id (the ruling’s permanent number at the courts’ site, e.g. 93117), collections (supreme, high, lower, administrative, labor, ip, ip_high; a ruling can sit in several), case_number (e.g. 平成21(オ)257) and case_year, title (the case name), ruling_date and ruling_date_japanese, year, court (with the bench for the Supreme Court), branch, department, judgment_type (判決, 決定), result (棄却, 破棄差戻…), reporter (the official reports citation), the lower court’s decision (lower_court, lower_case_number, lower_ruling_date, lower_result), the court’s own summary where it publishes one (holding for 判示事項, gist for 裁判要旨, statutes for 参照法条), field, the intellectual property fields (right_type, suit_type, ip_case_kind, invention, issues, appeal, appeal_result, ip_result), text_status (ok, scanned or missing), official_url (the ruling’s page at the courts), document_url (Croma’s copy of the court’s document, byte for byte as published) and source_document_url (the document’s own link at the courts). Fields the court does not state are null; the parties’ names are never fields.
Search results leave out the text. query still matches against it, so a phrase from the body finds the ruling; read the text itself with the Courts of Japan Ruling endpoint.

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One ruling, in full

POST /jp/courts-jp/ruling/v1 Dataset
Returns as_of, found, ruling_id and ruling, which carries everything the search returns plus content: a window onto the ruling’s full text, with text, offset, total_length, has_more and next_offset. Every result carries id (the ruling’s permanent number at the courts’ site, e.g. 93117), collections (supreme, high, lower, administrative, labor, ip, ip_high; a ruling can sit in several), case_number (e.g. 平成21(オ)257) and case_year, title (the case name), ruling_date and ruling_date_japanese, year, court (with the bench for the Supreme Court), branch, department, judgment_type (判決, 決定), result (棄却, 破棄差戻…), reporter (the official reports citation), the lower court’s decision (lower_court, lower_case_number, lower_ruling_date, lower_result), the court’s own summary where it publishes one (holding for 判示事項, gist for 裁判要旨, statutes for 参照法条), field, the intellectual property fields (right_type, suit_type, ip_case_kind, invention, issues, appeal, appeal_result, ip_result), text_status (ok, scanned or missing), official_url (the ruling’s page at the courts), document_url (Croma’s copy of the court’s document, byte for byte as published) and source_document_url (the document’s own link at the courts). Fields the court does not state are null; the parties’ names are never fields.
Long rulings are read a range at a time: send offset and limit, then pass the response’s next_offset back as offset until has_more is false. content is null when text_status is not ok; document_url still gives the court’s document.
An id the courts have not published returns found: false with HTTP 200, not an error.

Full reference

Schemas, all response fields, and an interactive playground.