Zen, Chinese Taoism embracing Indian Buddhism

The beginnings of Zen can be traced to India in the 3rd century when we have a school called Buddha Nature, which claimed that Buddha's emptiness is a gift we all share. That Buddha's nature is a connecting force between all that exists. 

The practice found a lot of traction in China through monks like Bodhidharma. The reason is that the interconnectedness the Buddhists were talking about matches the Tao, the connective substance, which is the basis of Taoism (one of the main Chinese schools of thought alongside Confucianism). From China, it moves to Japan, where the Zen name comes from.