The Lotus Sutra is prominent among the many sources quoted in writings of Japanese Zen master Dogen (1200--1253), highlighting the Mahayana context of his teachings and world-view. This work focuses on Dogen's use of the pivotal story in Lotus Sutra chapters fifteen and sixteen-myriad bodhisattvas emerging from underground and the inconceivable life-span of the Buddha---to express his own worldview of earth, space, and time as forces for spiritual awakening. The shift in perspective in this sutra story reflects a fundamental shift in East Asian Buddhist soteriology. A close reading of Dogen's references to this story reveals his hermeneutical play with its imagery of ground, space, and time, expressing immediate awakening beyond stages of cultivation. Dogen cites the inconceivable life-span story as an encouragement to present practice, in which he sees the enduring life of Sakyamuni Buddha. Dogen's presentation exemplifies the fundamental role of metaphor, images, and imagination in East Asian Mahayana practice and teaching. Dogen's view of space and ground as capable of awakening and spiritual agency influences his celebrated teachings on time, expressing the spatialization of temporality. The first chapter introduces the story in Lotus Sutra chapters fifteen and sixteen, discussing its pivotal role in the sutra's meaning and literary structure, and introduces Dogen's view of space awakening. Chapter two relates a series of hermeneutical and methodological issues involved in the Mahayana and for Dogen, including fundamental Buddhist hermeneutic stances; relevant modern hermeneutic perspectives, especially from Paul Ricoeur; and examples of influences from the Lotus Sutra on Dogen's discourse style. Chapter three traces responses and commentaries to Lotus Sutra chapters fifteen and sixteen from prominent East Asian Buddhist teachers, featuring early Chinese teachers Daosheng, Zhiyi, and Zhanran; Dogen's rough contemporaries in Japan, Saigyo Myoe, and Nichiren, and later Japanese Zen figures Hakuin, Ryokan, and the modern Shunryu Suzuki. Chapter four is a close reading of a range of references by Dogen to Lotus Sutra chapters fifteen and sixteen. Chapter five discusses Mahayana perspectives on earth, space, and time as context for Dogen's world-view. The Afterword suggests areas for further study.