The other main branch of Buddhism besides Theravada is Mahayana. “Mahayana” means “big chariot”. While Theravada Buddhism’s goal is merely to have the individual monk attain to nirvana, Mahayana tries to bring lots of people to enlightenment. Sometimes Theravada Buddhism is called “Hinayana Buddhism.” Hinayana means small chariot (it only tries to bring one person along. Mahayana Buddhism spread into China and thence to Korea, Japan, and Vietnam.
Historically what made the big difference between the two types of Buddhism is the concept of a Bodhisattva. A Bodhisattva is someone who has attained to nirvana, and thus could forever avoid being reincarnated, but who chooses to come back to earth again in order to help more people toward liberation. Over the centuries Mahayana Buddhism has branched out in a variety of ways. Bodhisattvas also came to be thought of as spiritual beings in the supernatural world that can help people in our world.
Zen Buddhism, which developed in China and Japan, is extremely different than the original teachings of the Buddha. It is mostly from Daoism, as can be seen in this quotation from the third Zen patriarch, Sengstan: “The Great Way is not difficult for those who have no preferences. When love and hat are both absent everything becomes clear and undisguised. Make the smallest distinction, however, and heaven and earth are set infinitely apart.”
The goal that is striven for in Zen Buddhism is not nirvana but the satori experience. The satori experience does not come about by turning inward, but by being extremely open to that which is outward. It is a relationship not with the mental representation of an object, but with the outside object that is represented in your mind. Recall that Hinduism believes that we are never in direct contact with the external object; the only things we directly experience of them are the internal representations of the external object....