# BR-DE-31 Direct debit requires the debited account identifier

When direct debit payment instructions (BG-19) are present, BT-91 debited account identifier must also be provided.

## Problem Description

When direct debit payment instructions (BG-19) are present, BT-91 debited account identifier must also be provided.

> **ERROR**: XRechnung 3.0

## Context and Significance

Direct debit cannot be processed safely without identifying the account to be debited.

## Solution

Add the buyer account identifier to BT-91 for direct debit, or use bank transfer payment instructions instead.

- validate
- convert

## Valid Examples

- Direct debit with BT-91 = DE89370400440532013000

## Invalid Examples

- Direct debit selected but BT-91 missing

## Technical Details

### Affected Fields
BG-19 Direct debit, BT-91 Debited account identifier

## Related Rules

- [BR-DE-30](/resources/kosit-validator-errors/br-de-30-direct-debit-requires-creditor-identifier)
- [BR-61](/resources/kosit-validator-errors/br-61-credit-transfer-account-required)

## Validation Tools

- [Official KoSIT Validator](https://erechnungsvalidator.service-bw.de/): Validate your XRechnung files against all BR-DE rules.
- [Convert PDF to XRechnung](/pdf-to-xrechnung): Automatic validation error fixes when converting.

## Related Resources

- [Official Specification](https://xeinkauf.de/xrechnung/)
- [Test Suite](https://github.com/itplr-kosit/xrechnung-testsuite)
- [Complete Error List](/resources/kosit-validator-errors): Overview of all German XRechnung validation rules.