Nichiren's career in thirteenth century Japan was marked by repeated confrontation with both religious rivals and the Kamakura shogunate, including exile to the Izu peninsula, a near-execution at Tatsunokuchi that he and his followers read as a miraculous escape, and a further exile to the remote island of Sado. Much of the Gosho was written during these hardships, addressed to specific named disciples and lay followers offering guidance, encouragement and doctrinal instruction under real and immediate pressure, giving the collection a personal, occasional character quite different from a systematically composed treatise. Its central teaching holds the Lotus Sutra to be the sole complete vehicle for liberation in the current degenerate age, mappo, expressed practically through the chanted invocation Nam-myoho-renge-kyo, the daimoku. The collection mixes short personal letters with longer formal treatises, most famously the Rissho Ankoku Ron, an appeal to the Kamakura authorities arguing that the country's troubles stemmed from following false Buddhist teachings rather than the Lotus Sutra alone.
Nichiren also wrote extensively on the Lotus Sutra's own claim that it alone, among all the Buddha's teachings, was suited to guide beings through the degenerate final age, a reading that placed his own writings, by extension, in the position of authoritative commentary on what he held to be Buddhism's single complete teaching.