If Tax accounting currency (ibt-006) is present, it shall be coded using JPY in ISO code list of 4217 a-3.
/ubl:Invoice[cac:AccountingSupplierParty/cac:Party/cac:PostalAddress/cac:Country/cbc:IdentificationCode = 'JP' ]not(exists(cbc:TaxCurrencyCode)) or cbc:TaxCurrencyCode/@schemeID = 'JPY'