The Humane King Sutra (Chinese: 仁王經; pinyin: rén wáng jīng; Japanese: 仁王経; rōmaji: Ninnō-gyō; Korean: 인왕경; romaja: inwang-gyeong; Vietnamese: Kinh Hộ Quốc) is found in Taisho No.
This sutra is unusual in the fact that its target audience, rather than being either lay practitioners or the community of monks and nuns, is the rulership (i.e. monarchs, presidents, prime ministers, etc.).
The foregrounded teachings, rather than being meditation and wisdom, are "humaneness" and "forbearance" or "ksanti", these being the most applicable religious values for the governance of a Buddhist state.
A second translation from a Sanskrit text was carried out a few centuries after the appearance of the original version, by the monk Amoghavajra (Bukong 不空), one of the most important figures in the Chinese Esoteric tradition, as well as a patriarch in the Shingon school of Japan.
This is famously quoted in the first line of The Tale of the Heike, whose latter half reads: "the color of the sāla flowers reveals the truth that the prosperous must decline."