Time of supply of goods sets tax liability at the earlier of invoice issuance or receipt of payment, with tailored rules for reverse charge and vouchers. Time of supply of goods arises at the earlier of invoice issuance (or the last required invoice date) and receipt of payment, with an option for small excess receipts to be treated as invoice date. For reverse charge supplies, time of supply is the earliest of receipt of goods, payment recorded or debited in the recipient's accounts, or the date after thirty days from the supplier's invoice; if indeterminable, the recipient's books control. Vouchers use issue or redemption dates. Unascertainable cases default to the periodical return date or the tax payment date. Additions to value take effect when received by the supplier.