Ninkū 仁空 (1309–1388) was a late-Kamakura / Nanboku-chō Tendai master and a major figure of the Hiei-zan precept-revival movement. He is associated with the Kurodani 黑谷 lineage of Mt. Hiei and with the Daijō-ji 大乘寺 / Saikyō-ji 西教寺 institutional complex at Sakamoto, on the slopes of Mt. Hiei. The Kurodani lineage was the principal medieval Tendai sub-school dedicated to the disciplined observance of the Brahmajāla bodhisattva precepts in the Tendai yuánjiè tradition, and Ninkū was one of its leading 14th-century systematizers.
His KR6t0080 Xīn-xué pú-sà xíng-yào chāo is the canonical procedural handbook of the Kurodani-Daijō-ji precept tradition, providing day-to-day liturgical regulations for the bodhisattva-bhikṣu under the Brahmajāla precept platform (six recollections, robe-and-bowl care, alms, time-meal, poṣadha, proxy-consent, rains-retreat, pravāraṇā, ordination procedure, lay-transformation regulations). The work was printed posthumously in 1400 by his disciple Myōkū 明空 of Rōzan-ji 廬山寺.
Ninkū should be situated as a forerunner of the Tendai Shingi-shū 天台真盛宗 tradition founded by his lineage-successor Shinsei 真盛 (1443–1495), and as a contemporary of the more famous Yōkaku 圓覺 / Yōkaku Shōnin of the kuden Tendai-precept-revival movement.
Within the Kanripo corpus his preserved work is KR6t0080 Xīnxué púsà xíngyào chāo.