Takuan (沢庵?), also known as takuwan or takuan-zuke and in Korean as danmuji (단무지), is pickled daikon radish. Takuan is often served alongside other types of tsukemono in traditional Japanese cuisine as well as banchan in traditional Korean cuisine, and is also enjoyed at the end of meals as it is thought to aid digestion.
The first step in the traditional process of making takuan is to hang a daikon radish in the sun for a few weeks until it becomes dehydrated and flexible. Next, the daikon is placed in a pickling crock and covered with a mix of salt, rice bran, optionally sugar, daikon greens, kombu, perhaps chilli pepper and/or dried persimmon peels. A weight is then placed on top of the crock, and the daikon is allowed to pickle for several months. The finished takuan is usually yellow in color and quite pungent, though most mass-produced takuan uses salt or syrup to reduce the dehydration time, and is colored artificially. Iburi-gakko (lit. smoked takuan) is eaten in Akita Prefecture. It is smoked rather than sun-dried before pickling.
Takuan Sōhō is credited with concocting this yellow pickle, which now bears his name.
Usually, takuan is washed with water, the excess brine removed and it is sliced thinly before serving. It is eaten as a side dish in meals, and eaten as a snack at teatime. Strip-cut takuan is often used for bento. Traditional takuan—using sun-dried daikon radish and pickled in rice bran bed—is sometimes stir fried or braised when getting older and sour. Some sushi rolls use strip-cut takuan for ingredients such as shinkomaki (takuan only), torotaku-maki (fatty tuna and takuan).