consumption-tax

Original🇨🇳 Chinese
Translated

This skill should be used when the user needs to calculate consumption tax or determine their tax method (20% Special Provision, Simplified Taxation, or Standard Taxation). Trigger phrases include: "Calculate consumption tax", "Consumption tax filing", "Consumption tax return form", "20% Special Provision", "Simplified Taxation", "Standard Taxation", "Taxable Sales", "Consumption Tax Amount", "Invoice", "Deemed Purchase Ratio", "Taxable Purchases"

2installs
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NPX Install

npx skill4agent add kazukinagata/shinkoku consumption-tax

SKILL.md Content (Chinese)

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Consumption Tax Calculation

A skill to calculate consumption tax from taxable sales and taxable purchases. This skill assumes that the user has been determined as a taxable business operator for consumption tax via the assess skill, and that settlement has been completed via the settlement skill. Calculation results are to be entered into the final return preparation section using the
/e-tax
skill (Claude in Chrome).

Load Settings (Execute First)

  1. Load
    shinkoku.config.yaml
    using the Read tool
  2. If the file does not exist, guide the user to execute the
    /setup
    skill and terminate
  3. Grasp the setting values, convert relative paths to absolute paths based on CWD:
    • db_path
      : Used for the
      --db-path
      argument of CLI scripts
    • output_dir
      : Base directory for outputting progress files, etc.
    • Each directory: Used when referencing files

Path Resolution Example

If
db_path
in config is
./shinkoku.db
and CWD is
/home/user/tax-2025/
:
  • shinkoku tax calc-consumption --input /home/user/tax-2025/output/consumption_input.json

Load Progress Information

After loading settings, load handover files to grasp results from previous steps.
  1. Load
    .shinkoku/progress/progress-summary.md
    using the Read tool (if it exists)
  2. Load the following handover files using the Read tool (if they exist):
    • .shinkoku/progress/06-settlement.md
    • .shinkoku/progress/02-assess.md
  3. Utilize the loaded information in subsequent steps (avoid re-asking the user)
  4. If files do not exist, skip and directly confirm necessary information with the user

Basic Policy

  • Start after confirming the determination result (taxable business operator judgment, filing method) from the assess skill
  • If the user is a tax-exempt business operator, guide them that consumption tax filing is not required and terminate
  • Perform calculations according to the filing method (20% Special Provision/Simplified Taxation/Standard Taxation)
  • Accurately distinguish tax rate categories (standard rate 10%/reduced rate 8%)
  • Make judgments in accordance with the classification rules in references/tax-classification.md

Prerequisite Confirmation

Confirm the following before starting consumption tax calculation:
  1. Are you a taxable business operator?: Confirm the determination result from the assess skill
  2. Confirmation of filing method: Confirm one of the following:
    • 20% Special Provision (transitional measure for those who became taxable business operators via Invoice registration)
    • Simplified Taxation (notification submitted, taxable sales in base period ≤ 50 million yen)
    • Standard Taxation (other cases)
  3. Tax period: Normally January 1 to December 31 (for sole proprietors)
  4. Are book data complete?: Settlement has been completed via the settlement skill

Filing Method Determination Flow

Q1. Did you become a taxable business operator through Invoice registration?
    AND is your taxable sales in the base period 10 million yen or less?
├── Yes → 20% Special Provision is applicable → Proceed to Q2
└── No → Proceed to Q3

Q2. Will you apply the 20% Special Provision?
├── Yes → Calculate using 20% Special Provision
└── No → Proceed to Q3 (You can choose the more favorable option between Simplified Taxation and Standard Taxation)

Q3. Have you submitted the Simplified Taxation System Selection Notification,
    AND is your taxable sales in the base period 50 million yen or less?
├── Yes → Calculate using Simplified Taxation
└── No → Calculate using Standard Taxation

Step 1: Aggregate Taxable Sales

Aggregate taxable sales by tax rate category from books. Calculate the following from results of
ledger.py trial-balance
or
ledger.py search
:

Aggregation Items

ItemDescription
Taxable Sales (tax-inclusive)Aggregate separately for 10% standard rate and 8% reduced rate
Taxable Sales (tax-exclusive)Tax base (round down amounts less than 1,000 yen)
Non-Taxable SalesNon-taxable transactions such as interest income
Tax-Exempt SalesExport transactions, etc. (if applicable)

Correspondence with Account Items

  • Sales (4001): Normally taxable sales (tax_category = taxable)
  • Interest Income (4100): Non-taxable sales (tax_category = non_taxable)
  • Miscellaneous Income (4110): Determine taxable/non-taxable based on content

Step 2: Calculate Consumption Tax Amount

Call
tax_calc.py calc-consumption

bash
shinkoku tax calc-consumption --input consumption_input.json
Input JSON (ConsumptionTaxInput):
json
{
  "fiscal_year": 2025,
  "method": "special_20pct",
  "taxable_sales_10": 5500000,
  "taxable_sales_8": 0,
  "taxable_purchases_10": 0,
  "taxable_purchases_8": 0,
  "simplified_business_type": null,
  "interim_payment": 0
}
Output (ConsumptionTaxResult):
  • method
    : Applied filing method
  • taxable_sales_total
    : Total taxable sales (tax-inclusive, for display)
  • taxable_base_10
    : Tax base (10% portion, tax-exclusive, rounded down to nearest 1,000 yen)
  • taxable_base_8
    : Tax base (8% portion, tax-exclusive, rounded down to nearest 1,000 yen)
  • national_tax_on_sales
    : Consumption tax amount (national tax: 7.8% portion + 6.24% portion)
  • tax_on_sales
    : = national_tax_on_sales (backward compatibility alias)
  • tax_on_purchases
    : Deductible purchase tax amount (national tax portion)
  • net_tax
    : Net tax amount (rounded down to nearest 100 yen, only if positive)
  • refund_shortfall
    : Refundable tax amount for insufficient deduction (if purchases > sales)
  • interim_payment
    : Interim tax payment amount
  • tax_due
    : Tax payable = net_tax - interim_payment
  • local_tax_due
    : Local consumption tax amount (net tax amount × 22/78, rounded down to nearest 100 yen)
  • total_due
    : Total tax payable (negative = refund)

Calculation Logic for 20% Special Provision

1. Tax base = Tax-inclusive sales × 100/110 (for 10% rate) or × 100/108 (for 8% rate)
   → Round down amounts less than 1,000 yen (National Tax Act Article 118)

2. Consumption tax amount (national tax) = Tax base × 7.8% (10% portion) + Tax base × 6.24% (8% portion)

3. Net tax amount = Consumption tax amount × 20%
   → Round down amounts less than 100 yen (National Tax Act Article 119)

4. Local consumption tax = Net tax amount × 22/78
   → Round down amounts less than 100 yen
  • Applicable to those who became taxable business operators via Invoice registration
  • Taxable sales in base period must be ≤ 10 million yen
  • Application deadline: Up to the tax period including September 30, 2026
  • No notification required (only need to indicate application on the return form)

Calculation Logic for Simplified Taxation

1. Tax base = Tax-inclusive sales × 100/110 (for 10% rate) or × 100/108 (for 8% rate)
   → Round down amounts less than 1,000 yen (National Tax Act Article 118)

2. Consumption tax amount (national tax) = Tax base × 7.8% (10% portion) + Tax base × 6.24% (8% portion)

3. Deductible purchase tax amount = Consumption tax amount × Deemed Purchase Ratio

4. Net tax amount = Consumption tax amount − Deductible purchase tax amount
   → Round down amounts less than 100 yen (National Tax Act Article 119)

5. Local consumption tax = Net tax amount × 22/78
   → Round down amounts less than 100 yen
Deemed Purchase Ratios (by business category):
Business CategoryApplicable BusinessesDeemed Purchase Ratio
Type 1Wholesale business90%
Type 2Retail business, agriculture/forestry/fisheries (food and beverages)80%
Type 3Manufacturing, agriculture/forestry/fisheries (other), construction, electricity/gas70%
Type 4Others (restaurants, etc.)60%
Type 5Service industry (transportation/communications/finance/insurance)50%
Type 6Real estate business40%
  • Freelancers (IT, design, consulting, etc.) are normally Type 5 (50% deemed purchase ratio)
  • If operating two or more businesses, calculate separately by business category in principle

Calculation Logic for Standard Taxation

1. Tax base = Tax-inclusive sales × 100/110 (for 10% rate) or × 100/108 (for 8% rate)
   → Round down amounts less than 1,000 yen (National Tax Act Article 118)

2. Consumption tax amount on taxable sales (national tax):
    Standard rate portion: Tax base × 78/1000 (=7.8%)
    Reduced rate portion: Tax base × 624/10000 (=6.24%)

3. Consumption tax amount on taxable purchases (national tax):
    Standard rate portion: Tax-inclusive purchase amount × 78/1100 (=7.8/110)
    Reduced rate portion: Tax-inclusive purchase amount × 624/10800 (=6.24/108)

4. Net tax amount = Consumption tax on sales − Consumption tax on purchases
   If positive → Round down amounts less than 100 yen (National Tax Act Article 119)
   If negative → Refundable tax amount for insufficient deduction (no rounding)

5. Local consumption tax = Net tax amount × 22/78
   → Round down amounts less than 100 yen
  • Preservation of eligible invoices (Invoice) is required for aggregating taxable purchases
  • Aggregate based on consumption tax classification in books (references/tax-classification.md)
  • If taxable sales ratio ≥95% and taxable sales ≤500 million yen, full deduction is allowed
  • For detailed requirements for input tax credit under the Invoice system, refer to
    skills/invoice-system/references/input-tax-credit-rules.md

Step 3: Comparison of Filing Methods (Optional)

If multiple methods are selectable, estimate tax amounts for each and present a comparison table.
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Consumption Tax Filing Method Comparison
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

| Method | Tax Payable | Notes |
|------|---------|------|
| 20% Special Provision | ¥○○,○○○ | No notification required |
| Simplified Taxation | ¥○○,○○○ | Notification required |
| Standard Taxation | ¥○○,○○○ | Invoice preservation required |

→ Most favorable method: [Method Name] (Difference: ¥○○,○○○)

Step 4: Presentation of Calculation Result Summary

━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━
Consumption Tax Calculation Results (FY ○ Reiwa)
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

■ Basic Information
  Filing Method:           [20% Special Provision / Simplified Taxation / Standard Taxation]
  Tax Period:           January 1 to December 31, Reiwa ○

■ Taxable Sales
  Standard Rate (10%) Applicable:  ¥○,○○○,○○○
  Reduced Rate (8%) Applicable:    ¥○○○,○○○
  Total Taxable Sales:     ¥○,○○○,○○○

■ Consumption Tax Amount
  Consumption Tax on Taxable Sales:     ¥○○○,○○○
  Deductible Purchase Tax Amount:           ¥○○○,○○○
  Net Tax Amount:                   ¥○○○,○○○
  Interim Tax Payment:                     ¥0
  -----------------------------------------
  Consumption Tax Payable:           ¥○○○,○○○
  Local Consumption Tax Payable:        ¥○○,○○○
  Total Tax Payable:               ¥○○○,○○○

■ Next Steps:
  → Enter into the final return preparation section using /e-tax (Claude in Chrome)
  → Prepare for submission using /submit
  → Consumption tax payment deadline: March 31, Reiwa ○
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Output Handover Documents

After presenting the summary, output the following files using the Write tool. This allows results to be carried over to the next step even if the session is interrupted or Compact occurs.

Output of Step-by-Step Files

Output in the following format to
.shinkoku/progress/08-consumption-tax.md
:
---
step: 8
skill: consumption-tax
status: completed
completed_at: "{Current Date YYYY-MM-DD}"
fiscal_year: {tax_year}
---

# Results of Consumption Tax Calculation & Return Preparation

## Filing Method

- Applied Method: {20% Special Provision/Simplified Taxation/Standard Taxation}

## Taxable Sales

- Standard Rate (10%) Applicable: ¥{Amount}
- Reduced Rate (8%) Applicable: ¥{Amount}
- Total Taxable Sales: ¥{Amount}

## Breakdown of Consumption Tax Amount

- Consumption Tax on Taxable Sales: ¥{Amount}
- Deductible Purchase Tax Amount: ¥{Amount}
- Net Tax Amount: ¥{Amount}

## Local Consumption Tax

- Local Consumption Tax Amount: ¥{Amount}

## Total Tax Payable

- Consumption Tax Payable: ¥{Amount}
- Local Consumption Tax Payable: ¥{Amount}
- **Total Tax Payable: ¥{Amount}**

## Next Steps

Enter into the final return preparation section using /e-tax (Claude in Chrome)
Prepare for submission using /submit
Consumption tax payment deadline: March 31, Reiwa {Year}
If consumption tax filing is not required (tax-exempt business operator), set status to
skipped
and describe content as "Filing not required as tax-exempt business operator".

Update Progress Summary

Update
.shinkoku/progress/progress-summary.md
(create new if it does not exist):
  • YAML frontmatter: fiscal_year, last_updated (current date), current_step: consumption-tax
  • Table: Update status of all steps (set consumption-tax to completed or skipped)
  • Guidance on next steps

Guidance After Output

After outputting files, inform the user of the following:
  • "Handover documents have been saved to
    .shinkoku/progress/
    . Results can be carried over to the next skill even if the session is interrupted."
  • Guidance on next steps

Disclaimer

  • This calculation is based on general consumption tax calculation logic
  • Judgment of business category for simplified taxation may vary depending on individual circumstances
  • It is recommended to confirm final filing content with a tax professional such as a tax accountant