The Threefold Lotus Sutra (法華三部経 pinyin: fǎ huá sān bù jīng, Jp: Hokke-sambu-kyo) is the composition of three complementary sutras that together form the "three-part Dharma flower sutra":
1. The Innumerable Meanings Sutra (無量義經 Ch: Wú Liáng Yì Jīng, Jp: Muryōgi Kyō), prologue to the Lotus Sutra. 2. The Lotus Sutra (妙法蓮華經 Ch: Miào Fǎ Lián Huá Jīng, Jp: Myōhō Renge Kyō) itself. 3. The Sutra of Meditation on the Bodhisattva Universal Virtue/Samantabhadra Meditation Sutra (普賢經 Ch: Pǔ Xián Jīng, Jp: Fugen Kyō), epilogue to the Lotus Sutra.They have been known collectively as the Threefold Lotus Sutra in China and Japan since ancient times.
References
Threefold Lotus Sutra Wikipedia(Text) CC BY-SA