Dogen transmitted Dongshan Liangjie’s Caodong Zen lineage and school to Japan where it eventually became known as the Soto school.   Early in life he lost both of his parents and entered the life of a Buddhist monk while still his teens.  He initially practiced within the Tendai school of Buddhism but was dissatisfied with the practice there because he could not answer his “great doubt” of why one needs to practice if they are already inherently awakened.  He eventually took up the path of Zen and traveled to China to practice there.  He eventually met the Caodong master Rujing and inherited his Dharma.  He returned to Japan and developed the first traditional Song-style Zen monastery in that country.