# BT-10 — Buyer reference

> https://billhorse.com/en/terms/bt-10/

Reference provided by the buyer so they can route the invoice internally. In Germany it is the central routing field for public-sector invoices.

## Practical note

For invoices to German public bodies this field carries the Leitweg-ID (pattern: 04011000-12345-03); XRechnung makes BT-10 mandatory in general. For B2B any buyer reference is fine.

## Where does it live in the XML?

- UBL: `cbc:BuyerReference`
- CII: `rsm:SupplyChainTradeTransaction/ram:ApplicableHeaderTradeAgreement/ram:BuyerReference`

## Checked by these rules

- [BR-DE-15 — Buyer reference/Leitweg-ID missing (XRechnung)](https://billhorse.com/en/rules/br-de-15/)
- [BH-LEITWEG-01 — Buyer reference not in Leitweg format](https://billhorse.com/en/rules/bh-leitweg-01/)