Sakamoto Legal Office

The Problem#

• Japanese estate administration requires obtaining koseki (family register) records from every municipality where the deceased was ever registered — birth, marriage, divorce, and death may each be in different cities
• The judicial scrivener must compile a complete family tree to identify all legal heirs, then prepare an isan bunkatsu kyogisho (estate division agreement) requiring unanimous consent of every heir and their registered inkan (personal seal)
• The process is entirely paper-based: koseki records are physical documents, the division agreement must be physically sealed, and the Legal Affairs Bureau requires originals
• A typical estate takes 4–6 months of administrative work, and in ~10% of cases a previously unknown heir is discovered late, forcing the division agreement to be restarted

How They’d Use INHERIT#

• The japan extension’s KosekiRecord[] entries record honseki (registered domicile), kosekiHead (head of the family register), and kosekiReference for each person — building the family tree progressively as records arrive from each municipality
• IryubunClaim[] pre-calculates each heir’s reserved share — reservedFraction (e.g. "1/4" for a child when both spouse and children exist) — allowing Sakamoto to identify potential disputes before they arise
• The isanBunkatsu object records the estate division agreement: type (consultation, mediation, or adjudication), each heir’s consent status, and the agreed distribution
• YoshiAdoption[] records adopted family members — critical in Japan where adult adoption (yoshi) for succession is common, with adoptionType distinguishing "futsu_yoshi" (regular) from "tokubetsu_yoshi" (special, severing biological ties)
• The inkanVerified boolean confirms that registered seals have been verified at the Legal Affairs Bureau

The Integration#

• Export-focused: Sakamoto generates INHERIT documents for submission to the Legal Affairs Bureau (for property registration transfer) and to financial institutions (for account release)
• The structured format replaces the current practice of physically carrying koseki records and sealed division agreements to each institution
• Progressive data entry means the INHERIT document grows as koseki records are obtained, giving Sakamoto a real-time view of the emerging family tree

The Business Case#

• Digitised koseki compilation reduces family tree research from 6–8 weeks to 2–3 weeks
• Across 60–70 cases per year, this saves approximately 300 hours annually
• Structured isanBunkatsu format identifies missing heir consents early — preventing the ~10% of cases where the division agreement must be restarted due to a late-discovered heir
• Total annual savings estimated at ¥4.5 million (approximately £24,000) — substantial for a three-person office

Before / After#

Without INHERIT:

1. Client’s family member dies — Sakamoto requests koseki records from multiple municipalities by post
2. Records arrive over 6–8 weeks; Sakamoto manually compiles the family tree from paper documents
3. An estate division agreement is drafted and circulated to all known heirs for inkan sealing
4. A previously unknown heir is discovered after three heirs have already sealed — the agreement must be restarted
5. Sakamoto physically carries original documents to the Legal Affairs Bureau and each financial institution
6. Total administration time: 4–6 months

With INHERIT:

1. Client’s family member dies — Sakamoto begins building KosekiRecord[] entries as records arrive
2. The family tree in kinship.json grows progressively; IryubunClaim[] flags all potential heirs and their reserved shares
3. Missing heirs are identified before the division agreement is drafted — no restarts
4. The isanBunkatsu agreement is structured, sealed, and submitted digitally to the Legal Affairs Bureau
5. Total administration time: 2–3 months