If the definition of zen is foggy for you, read this.
From the page: "Buddhism originated in India about 500 BC and slowly spread to other parts of Asia. The buddhist teachings reached China about 100 BC but it took a few hundred years for buddhism to become a vital part of Chinese culture.
Once the teachings had arrived in China the practices were naturally transformed by the Chinese psyche and temperament. Out of all the ingenious forms of buddhism that appeared in China, chan became the most popular tradition.
Round 600 AD, buddhism reached the Japanese shore where the practices gradually took on a distinctive Japanese flavor. The tradition was given the name zen. "