電子帳簿保存法 — スキャナ保存と電子取引保存の対応

The Electronic Books Preservation Act, enacted in 1998, permits national-tax-related ledgers and documents to be preserved as electromagnetic records (electronic data). In contrast to the traditional system where paper preservation was the default, this law promotes corporate paperless adoption by allowing data to remain in electronic form when certain requirements are met.

The January 2022 amendment significantly relaxed requirements and abolished the prior tax-office pre-approval system. At the same time, electronic preservation of electronic transaction data became mandatory, and after a two-year grace period this requirement has been fully enforced since January 2024.

The Act divides preservation into three categories based on the document type and preservation method. Each has different requirements and obligations, and practical implementation must be considered separately for each.

This category covers ledgers originally created on computer (journals, general ledger, cashbooks, etc.) and financial closing documents, preserved as electronic data. This category is OPTIONAL — printing and preserving on paper continues to be permitted.

The 2022 amendment reorganized this into two tiers: "high-quality electronic ledgers" and "other electronic ledgers." Filing a notification as a high-quality electronic ledger (one that retains correction/deletion history, has mutual relevance among data, and satisfies search functionality) provides an incentive of a 5% reduction in the underreporting additional tax (Article 65 of the General Tax Law).

This category covers paper documents received or created (invoices, receipts, contracts, etc.) that are scanned with a scanner or smartphone, converted to electronic data, and after which the originals may be discarded. This is also OPTIONAL but its requirements are strict.

Transaction information that was exchanged electronically from the start (PDF invoices attached to email, EDI transactions, cloud-service transactions, purchase data from Amazon/Rakuten, etc.) MUST be preserved electronically. Even if you print it out, you still need to preserve the electronic original alongside.

This has been fully mandated since January 2024 and the grace period has ended. However, under the new deferral measure, if there is a reasonable reason and the business maintains the ability to respond to printed-document and download requests, electronic data preservation continues to be required, but it is permitted without satisfying the search requirements.

The Act's requirements can be organized around two perspectives: ensuring authenticity and ensuring visibility of electronic data. These are the fundamental principles for conferring on electronic data the same level of reliability as paper documents.

By default, search must be possible by three items: (1) transaction date, (2) transaction amount, (3) counterparty. Furthermore, date and amount must support range queries (from–to), and combined searches across two or more items must also be possible.

Timestamps must be issued by Time Stamp Authorities (TSA) accredited by the Japan Data Communications Association (JADAC) for time-authentication services. Applying a timestamp to data guarantees that the data existed at that time (proof of existence) and that it has not been tampered with since (proof of non-tampering).

The 2022 amendment extended the timestamp application deadline up to "approximately 2 months + approximately 7 business days." Additionally, when using cloud services that retain correction/deletion history (including systems where correction/deletion is not possible), timestamp application is no longer required.

The Japan Image and Information Management Association (JIIMA) operates a certification program confirming that electronic-ledger and document software meets the Act's requirements. Certified products are also published on the National Tax Agency's website. In practice, selecting certified software makes the determination of requirement compliance easy.

The most important practical task is building a workflow that systematically preserves electronic transaction data. The challenge many companies face is that invoice PDFs end up scattered across individuals' email inboxes, making unified storage and searching difficult.

The recommended approach is threefold: (1) introduce cloud storage or dedicated software for centralized preservation; (2) include date, amount, and counterparty in filenames (or create an index file); (3) prepare operational rules and clarify rules for correction and deletion.

If electronic transaction data is preserved in a way that fails to satisfy the Act's requirements, blue-form return approval may potentially be revoked (though revocation is not immediate and is judged considering the overall situation). Additionally, in cases of concealment or disguise, the heavy additional tax is increased by 10% above normal (Article 8, Paragraph 5).