Tanden location

Here is an interesting video by Bill Douglas, the founder of World Tai Chi Day -  with down to earth explanation to help you localize your Dan Tien (Tan Den in Japanese).

Now this is not only important for Tai Chi or Chi Gong, it is important for ALL martial Arts (Budō 武道), as well as Zen (禪). Actually, it is also very important in other ways such as Calligraphy (shodō 書道,. 

No matter which discipline you practice, your Movement and Intention needs to begin there. 

There actually are 3 Dantien : The Lower, Middle and Higher Dantien. The Higher is located in the brain, the Middle one in the heart area, and the Lower one in the lower abdomen. Because this one is the most important, it is generally referred as the Dantien. This isthe Dantien Bill Douglas speaks about in this video.