Many businesses make preventable mistakes when implementing electronic ledger systems. This article covers the most common errors and how to avoid them.

Mistake 1: Scanning at Low Resolution

Scanning receipts at too low a resolution makes text illegible over time and can lead to tax authority rejection. Always scan at 300 DPI minimum. For thermal receipts that fade over time, scan at 400 DPI or higher. Store the original until the statute of limitations expires, even after scanning.

Mistake 2: Failing to Preserve Original Electronic Files

A critical requirement of the electronic bookkeeping act is that documents received electronically (email PDF invoices, web download receipts) must be stored in their original format. Converting them to different file formats or printing and scanning them is not permitted. Keep the original PDF exactly as received, with all metadata intact.

Mistake 3: Inconsistent File Naming

Without a consistent naming system, finding specific documents during an audit becomes impossible. Establish a naming convention and enforce it across the organization. Include at minimum the date, vendor name, type (invoice/receipt), and a unique identifier. Example: 2025-08-15_Abe-Supply_Invoice_001234.pdf.

Mistake 4: No Backup Strategy

Relying on a single storage location is risky. Hard drive failures, cloud service outages, or accidental deletions can lead to data loss. Maintain at least three copies: your primary working copy (cloud or local), a local backup (external drive), and an off-site backup. Test restoration procedures annually.

Mistake 5: Ignoring Retention Periods

Japanese tax law requires different retention periods for different documents. Invoices related to income tax must be kept for 5 years. Invoices related to consumption tax must be kept for 7 years. Wage records must be kept for 5 years. Set up automated retention scheduling in your software so documents are not deleted prematurely.

Mistake 6: Not Keeping an Audit Trail

The electronic bookkeeping act requires a clear audit trail showing when documents were received, when they were modified, and by whom. Some businesses use simple file storage without audit trail features. Choose software that automatically logs all operations and never allows users to modify stored documents directly.

Summary

Avoiding these common mistakes requires understanding the legal requirements and implementing systematic processes. Invest time upfront to set up proper workflows—it will save significant trouble during tax audits.