Takuan is a Japanese dish of fermented daikon radish. It is a form of Tsukemono (Japanese pickled veggies), which are served as side dishes or snacks, and are even part of the Japanese tea ceremony. Takuan in particular is often served at the end of meal to help digestion. The name “Takuan” is often attributed to Takuan Soho, a 17th century Zen Buddhist figure and the creative basis for the character Dakuan from the anime film Ninja Scroll. Korean cuisine has a similar pickled daikon radish dish, called Danmuji (단무지).
The daikon radish itself made its way to Japan from China about 2,000 years ago. Today, more land in Japan is used to grow daikon than any other vegetable. Takuan sold in many stores today is dyed yellow with food coloring; I was able to get a similar color by using a tiny bit of turmeric while pickling the radishes.