From October 1st2023, Seller Tax identifier (ibt-031) shall be coded by using a Registration number for Qualified Invoice in Japan, which consists of 14 digits that starts with T.
/ubl:Invoice[cac:AccountingSupplierParty/cac:Party/cac:PostalAddress/cac:Country/cbc:IdentificationCode = 'JP' ]/cac:AccountingSupplierParty/cac:Party/cac:PartyTaxScheme[cac:TaxScheme/normalize-space(upper-case(cbc:ID))='VAT']matches(normalize-space(cbc:CompanyID),'^T[0-9]{13}$')