Consumption Tax

This handles Japanese consumption tax calculations for sole proprietors, walking you through the three main filing methods (2割特例, 簡易課税, 本則課税) based on your invoice registration status and revenue thresholds. It reads from shinkoku.config.yaml, pulls data from your bookkeeping ledger, calculates tax amounts by rate bracket (10% standard, 8% reduced), and writes results to progress files so you can pick up where you left off after a session break. The comparisons between methods are helpful since the best choice depends on your purchase deductions. Designed to feed into the e-tax filing system, with the usual disclaimer that you should verify everything with a tax professional before actually submitting.