The first one was the same. Both denominations are part of Buddhism and is part of the Mahayana branch to another place. In Sanskrit, the word “vajra” means a diamond or a thunderbolt. And “Chan” is a translation into Chinese of the Sanskrit word “dhyana,” which simply means meditation. Vajrayana is best known from Tibet and Zen is best known from Japan, but it also historically spread to China and Japan. When Buddhism came to China, there were three kinds of Buddhist masters: (1) specialists in vinaya(rules for monks and nuns), (2) specialists in dhyana(meditation), and (3) specialists in Dharma (Buddhist texts). According to Vajrayana doctrine, there were three turnings of the Wheel of the Dharma, represented by the three main branches of Buddhism. According to Zen texts, when the Buddha was going to preach one day, he simply sat quietly. This was the start of the transmission of Zen Buddhism. The Buddha is said to have taught the wisdom that became Mahayana (the path of the bodhisattva), in which it was taught that enlightenment was a sudden event. The goal of the Vajrayana and Zen, as in Mahayana, is to become a bodhisattva. That means that one seeks enlightenment, but postpones final nirvana so as to stay in the world of samsara and help others reach nirvana first.