The terms 'the Land of the Rising Sun' and 'the Land of the Setting Sun' are simply Buddhist terms which refer to the east and the west, as "Daichidoron" (Commentary on the Great Wisdom Sutra), an annotated edition of "Makahannyaharamitashingyo" (The Great Treatise on Perfection of Wisdom), says that the land of the rising sun is the east, and the land of the setting sun is the west.
「日出處」「日沒處」は『摩訶般若波羅蜜多経』の注釈書『大智度論』に日出処是東方日没処是西方　とあるなど、単に東西の方角を表す仏教用語である。