No easyRates shipping methods allows for the Tariff duty to be paid by the shipper.
In Japan Post, most international shipping methods are set for the Tariff duty to be paid by the addressee.
However, there is one shipping method that allows for Tariff duty to be paid by the shipper. The shipping method is called "U-Global Express". However, this shipping method is not supported with easyRates so while using easyRates the addressee needs to pay for the Tariff duty.